Chapter 5. Troubleshooting logging

5.1. Viewing Logging status

You can view the status of the Red Hat OpenShift Logging Operator and other logging components.

5.1.1. Viewing the status of the Red Hat OpenShift Logging Operator

You can view the status of the Red Hat OpenShift Logging Operator.

Prerequisites

The Red Hat OpenShift Logging Operator and OpenShift Elasticsearch Operator are installed.

Procedure

Change to the openshift-logging project by running the following command:
```
$ oc project openshift-logging
```

Get the ClusterLogging instance status by running the following command:

$ oc get clusterlogging instance -o yaml

Example output

apiVersion: logging.openshift.io/v1
kind: ClusterLogging
# ...
status:  1
  collection:
    logs:
      fluentdStatus:
        daemonSet: fluentd  2
        nodes:
          collector-2rhqp: ip-10-0-169-13.ec2.internal
          collector-6fgjh: ip-10-0-165-244.ec2.internal
          collector-6l2ff: ip-10-0-128-218.ec2.internal
          collector-54nx5: ip-10-0-139-30.ec2.internal
          collector-flpnn: ip-10-0-147-228.ec2.internal
          collector-n2frh: ip-10-0-157-45.ec2.internal
        pods:
          failed: []
          notReady: []
          ready:
          - collector-2rhqp
          - collector-54nx5
          - collector-6fgjh
          - collector-6l2ff
          - collector-flpnn
          - collector-n2frh
  logstore: 3
    elasticsearchStatus:
    - ShardAllocationEnabled:  all
      cluster:
        activePrimaryShards:    5
        activeShards:           5
        initializingShards:     0
        numDataNodes:           1
        numNodes:               1
        pendingTasks:           0
        relocatingShards:       0
        status:                 green
        unassignedShards:       0
      clusterName:             elasticsearch
      nodeConditions:
        elasticsearch-cdm-mkkdys93-1:
      nodeCount:  1
      pods:
        client:
          failed:
          notReady:
          ready:
          - elasticsearch-cdm-mkkdys93-1-7f7c6-mjm7c
        data:
          failed:
          notReady:
          ready:
          - elasticsearch-cdm-mkkdys93-1-7f7c6-mjm7c
        master:
          failed:
          notReady:
          ready:
          - elasticsearch-cdm-mkkdys93-1-7f7c6-mjm7c
visualization:  4
    kibanaStatus:
    - deployment: kibana
      pods:
        failed: []
        notReady: []
        ready:
        - kibana-7fb4fd4cc9-f2nls
      replicaSets:
      - kibana-7fb4fd4cc9
      replicas: 1

1: In the output, the cluster status fields appear in the status stanza.
2: Information on the Fluentd pods.
3: Information on the Elasticsearch pods, including Elasticsearch cluster health, green, yellow, or red.
4: Information on the Kibana pods.

5.1.1.1. Example condition messages

The following are examples of some condition messages from the Status.Nodes section of the ClusterLogging instance.

A status message similar to the following indicates a node has exceeded the configured low watermark and no shard will be allocated to this node:

Example output

  nodes:
  - conditions:
    - lastTransitionTime: 2019-03-15T15:57:22Z
      message: Disk storage usage for node is 27.5gb (36.74%). Shards will be not
        be allocated on this node.
      reason: Disk Watermark Low
      status: "True"
      type: NodeStorage
    deploymentName: example-elasticsearch-clientdatamaster-0-1
    upgradeStatus: {}

A status message similar to the following indicates a node has exceeded the configured high watermark and shards will be relocated to other nodes:

Example output

  nodes:
  - conditions:
    - lastTransitionTime: 2019-03-15T16:04:45Z
      message: Disk storage usage for node is 27.5gb (36.74%). Shards will be relocated
        from this node.
      reason: Disk Watermark High
      status: "True"
      type: NodeStorage
    deploymentName: cluster-logging-operator
    upgradeStatus: {}

A status message similar to the following indicates the Elasticsearch node selector in the CR does not match any nodes in the cluster:

Example output

    Elasticsearch Status:
      Shard Allocation Enabled:  shard allocation unknown
      Cluster:
        Active Primary Shards:  0
        Active Shards:          0
        Initializing Shards:    0
        Num Data Nodes:         0
        Num Nodes:              0
        Pending Tasks:          0
        Relocating Shards:      0
        Status:                 cluster health unknown
        Unassigned Shards:      0
      Cluster Name:             elasticsearch
      Node Conditions:
        elasticsearch-cdm-mkkdys93-1:
          Last Transition Time:  2019-06-26T03:37:32Z
          Message:               0/5 nodes are available: 5 node(s) didn't match node selector.
          Reason:                Unschedulable
          Status:                True
          Type:                  Unschedulable
        elasticsearch-cdm-mkkdys93-2:
      Node Count:  2
      Pods:
        Client:
          Failed:
          Not Ready:
            elasticsearch-cdm-mkkdys93-1-75dd69dccd-f7f49
            elasticsearch-cdm-mkkdys93-2-67c64f5f4c-n58vl
          Ready:
        Data:
          Failed:
          Not Ready:
            elasticsearch-cdm-mkkdys93-1-75dd69dccd-f7f49
            elasticsearch-cdm-mkkdys93-2-67c64f5f4c-n58vl
          Ready:
        Master:
          Failed:
          Not Ready:
            elasticsearch-cdm-mkkdys93-1-75dd69dccd-f7f49
            elasticsearch-cdm-mkkdys93-2-67c64f5f4c-n58vl
          Ready:

A status message similar to the following indicates that the requested PVC could not bind to PV:

Example output

      Node Conditions:
        elasticsearch-cdm-mkkdys93-1:
          Last Transition Time:  2019-06-26T03:37:32Z
          Message:               pod has unbound immediate PersistentVolumeClaims (repeated 5 times)
          Reason:                Unschedulable
          Status:                True
          Type:                  Unschedulable

A status message similar to the following indicates that the Fluentd pods cannot be scheduled because the node selector did not match any nodes:

Example output

Status:
  Collection:
    Logs:
      Fluentd Status:
        Daemon Set:  fluentd
        Nodes:
        Pods:
          Failed:
          Not Ready:
          Ready:

5.1.2. Viewing the status of logging components

You can view the status for a number of logging components.

Prerequisites

The Red Hat OpenShift Logging Operator and OpenShift Elasticsearch Operator are installed.

Procedure

Change to the openshift-logging project.
```
$ oc project openshift-logging
```

View the status of logging environment:

$ oc describe deployment cluster-logging-operator

Example output

Name:                   cluster-logging-operator

....

Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable

....

Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  62m   deployment-controller  Scaled up replica set cluster-logging-operator-574b8987df to 1----

View the status of the logging replica set:

Get the name of a replica set:

Example output

$ oc get replicaset

Example output

NAME                                      DESIRED   CURRENT   READY   AGE
cluster-logging-operator-574b8987df       1         1         1       159m
elasticsearch-cdm-uhr537yu-1-6869694fb    1         1         1       157m
elasticsearch-cdm-uhr537yu-2-857b6d676f   1         1         1       156m
elasticsearch-cdm-uhr537yu-3-5b6fdd8cfd   1         1         1       155m
kibana-5bd5544f87                         1         1         1       157m

Get the status of the replica set:

$ oc describe replicaset cluster-logging-operator-574b8987df

Example output

Name:           cluster-logging-operator-574b8987df

....

Replicas:       1 current / 1 desired
Pods Status:    1 Running / 0 Waiting / 0 Succeeded / 0 Failed

....

Events:
  Type    Reason            Age   From                   Message
  ----    ------            ----  ----                   -------
  Normal  SuccessfulCreate  66m   replicaset-controller  Created pod: cluster-logging-operator-574b8987df-qjhqv----

5.2. Troubleshooting log forwarding

5.2.1. Redeploying Fluentd pods

When you create a ClusterLogForwarder custom resource (CR), if the Red Hat OpenShift Logging Operator does not redeploy the Fluentd pods automatically, you can delete the Fluentd pods to force them to redeploy.

Prerequisites

You have created a ClusterLogForwarder custom resource (CR) object.

Procedure

Delete the Fluentd pods to force them to redeploy by running the following command:
```
$ oc delete pod --selector logging-infra=collector
```

5.2.2. Troubleshooting Loki rate limit errors

If the Log Forwarder API forwards a large block of messages that exceeds the rate limit to Loki, Loki generates rate limit (429) errors.

These errors can occur during normal operation. For example, when adding the logging to a cluster that already has some logs, rate limit errors might occur while the logging tries to ingest all of the existing log entries. In this case, if the rate of addition of new logs is less than the total rate limit, the historical data is eventually ingested, and the rate limit errors are resolved without requiring user intervention.

In cases where the rate limit errors continue to occur, you can fix the issue by modifying the LokiStack custom resource (CR).

Important

The LokiStack CR is not available on Grafana-hosted Loki. This topic does not apply to Grafana-hosted Loki servers.

Conditions

The Log Forwarder API is configured to forward logs to Loki.

Your system sends a block of messages that is larger than 2 MB to Loki. For example:

"values":[["1630410392689800468","{\"kind\":\"Event\",\"apiVersion\":\
.......
......
......
......
\"received_at\":\"2021-08-31T11:46:32.800278+00:00\",\"version\":\"1.7.4 1.6.0\"}},\"@timestamp\":\"2021-08-31T11:46:32.799692+00:00\",\"viaq_index_name\":\"audit-write\",\"viaq_msg_id\":\"MzFjYjJkZjItNjY0MC00YWU4LWIwMTEtNGNmM2E5ZmViMGU4\",\"log_type\":\"audit\"}"]]}]}

After you enter oc logs -n openshift-logging -l component=collector, the collector logs in your cluster show a line containing one of the following error messages:

429 Too Many Requests Ingestion rate limit exceeded

Example Vector error message

2023-08-25T16:08:49.301780Z  WARN sink{component_kind="sink" component_id=default_loki_infra component_type=loki component_name=default_loki_infra}: vector::sinks::util::retries: Retrying after error. error=Server responded with an error: 429 Too Many Requests internal_log_rate_limit=true

Example Fluentd error message

2023-08-30 14:52:15 +0000 [warn]: [default_loki_infra] failed to flush the buffer. retry_times=2 next_retry_time=2023-08-30 14:52:19 +0000 chunk="604251225bf5378ed1567231a1c03b8b" error_class=Fluent::Plugin::LokiOutput::LogPostError error="429 Too Many Requests Ingestion rate limit exceeded for user infrastructure (limit: 4194304 bytes/sec) while attempting to ingest '4082' lines totaling '7820025' bytes, reduce log volume or contact your Loki administrator to see if the limit can be increased\n"

The error is also visible on the receiving end. For example, in the LokiStack ingester pod:

Example Loki ingester error message

level=warn ts=2023-08-30T14:57:34.155592243Z caller=grpc_logging.go:43 duration=1.434942ms method=/logproto.Pusher/Push err="rpc error: code = Code(429) desc = entry with timestamp 2023-08-30 14:57:32.012778399 +0000 UTC ignored, reason: 'Per stream rate limit exceeded (limit: 3MB/sec) while attempting to ingest for stream

Procedure

Update the ingestionBurstSize and ingestionRate fields in the LokiStack CR:
```
apiVersion: loki.grafana.com/v1
kind: LokiStack
metadata:
  name: logging-loki
  namespace: openshift-logging
spec:
  limits:
    global:
      ingestion:
        ingestionBurstSize: 16 1
        ingestionRate: 8 2
# ...
```
1
The ingestionBurstSize field defines the maximum local rate-limited sample size per distributor replica in MB. This value is a hard limit. Set this value to at least the maximum logs size expected in a single push request. Single requests that are larger than the ingestionBurstSize value are not permitted.
2
The ingestionRate field is a soft limit on the maximum amount of ingested samples per second in MB. Rate limit errors occur if the rate of logs exceeds the limit, but the collector retries sending the logs. As long as the total average is lower than the limit, the system recovers and errors are resolved without user intervention.

5.3. Troubleshooting logging alerts

You can use the following procedures to troubleshoot logging alerts on your cluster.

5.3.1. Elasticsearch cluster health status is red

At least one primary shard and its replicas are not allocated to a node. Use the following procedure to troubleshoot this alert.

Tip

Some commands in this documentation reference an Elasticsearch pod by using a $ES_POD_NAME shell variable. If you want to copy and paste the commands directly from this documentation, you must set this variable to a value that is valid for your Elasticsearch cluster.

You can list the available Elasticsearch pods by running the following command:

$ oc -n openshift-logging get pods -l component=elasticsearch

Choose one of the pods listed and set the $ES_POD_NAME variable, by running the following command:

$ export ES_POD_NAME=<elasticsearch_pod_name>

You can now use the $ES_POD_NAME variable in commands.

Procedure

Check the Elasticsearch cluster health and verify that the cluster status is red by running the following command:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME -- health
```

List the nodes that have joined the cluster by running the following command:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_cat/nodes?v

List the Elasticsearch pods and compare them with the nodes in the command output from the previous step, by running the following command:
```
$ oc -n openshift-logging get pods -l component=elasticsearch
```
If some of the Elasticsearch nodes have not joined the cluster, perform the following steps.
1. Confirm that Elasticsearch has an elected master node by running the following command and observing the output:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_cat/master?v
```
2. Review the pod logs of the elected master node for issues by running the following command and observing the output:
```
$ oc logs <elasticsearch_master_pod_name> -c elasticsearch -n openshift-logging
```
3. Review the logs of nodes that have not joined the cluster for issues by running the following command and observing the output:
```
$ oc logs <elasticsearch_node_name> -c elasticsearch -n openshift-logging
```
If all the nodes have joined the cluster, check if the cluster is in the process of recovering by running the following command and observing the output:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_cat/recovery?active_only=true
```
If there is no command output, the recovery process might be delayed or stalled by pending tasks.

Check if there are pending tasks by running the following command and observing the output:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- health | grep number_of_pending_tasks

If there are pending tasks, monitor their status. If their status changes and indicates that the cluster is recovering, continue waiting. The recovery time varies according to the size of the cluster and other factors. Otherwise, if the status of the pending tasks does not change, this indicates that the recovery has stalled.
If it seems like the recovery has stalled, check if the cluster.routing.allocation.enable value is set to none, by running the following command and observing the output:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_cluster/settings?pretty
```

If the cluster.routing.allocation.enable value is set to none, set it to all, by running the following command:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_cluster/settings?pretty \
  -X PUT -d '{"persistent": {"cluster.routing.allocation.enable":"all"}}'

Check if any indices are still red by running the following command and observing the output:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_cat/indices?v

If any indices are still red, try to clear them by performing the following steps.

Clear the cache by running the following command:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=<elasticsearch_index_name>/_cache/clear?pretty

Increase the max allocation retries by running the following command:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=<elasticsearch_index_name>/_settings?pretty \
  -X PUT -d '{"index.allocation.max_retries":10}'

Delete all the scroll items by running the following command:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_search/scroll/_all -X DELETE

Increase the timeout by running the following command:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=<elasticsearch_index_name>/_settings?pretty \
  -X PUT -d '{"index.unassigned.node_left.delayed_timeout":"10m"}'

If the preceding steps do not clear the red indices, delete the indices individually.

Identify the red index name by running the following command:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_cat/indices?v

Delete the red index by running the following command:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=<elasticsearch_red_index_name> -X DELETE

If there are no red indices and the cluster status is red, check for a continuous heavy processing load on a data node.
1. Check if the Elasticsearch JVM Heap usage is high by running the following command:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_nodes/stats?pretty
```
  In the command output, review the node_name.jvm.mem.heap_used_percent field to determine the JVM Heap usage.
2. Check for high CPU utilization. For more information about CPU utilitzation, see the OpenShift Container Platform "Reviewing monitoring dashboards" documentation.

Additional resources

5.3.2. Elasticsearch cluster health status is yellow

Replica shards for at least one primary shard are not allocated to nodes. Increase the node count by adjusting the nodeCount value in the ClusterLogging custom resource (CR).

Additional resources

Fix a red or yellow cluster status

5.3.3. Elasticsearch node disk low watermark reached

Elasticsearch does not allocate shards to nodes that reach the low watermark.

Tip

You can list the available Elasticsearch pods by running the following command:

$ oc -n openshift-logging get pods -l component=elasticsearch

Choose one of the pods listed and set the $ES_POD_NAME variable, by running the following command:

$ export ES_POD_NAME=<elasticsearch_pod_name>

You can now use the $ES_POD_NAME variable in commands.

Procedure

Identify the node on which Elasticsearch is deployed by running the following command:
```
$ oc -n openshift-logging get po -o wide
```

Check if there are unassigned shards by running the following command:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_cluster/health?pretty | grep unassigned_shards

If there are unassigned shards, check the disk space on each node, by running the following command:

$ for pod in `oc -n openshift-logging get po -l component=elasticsearch -o jsonpath='{.items[*].metadata.name}'`; \
  do echo $pod; oc -n openshift-logging exec -c elasticsearch $pod \
  -- df -h /elasticsearch/persistent; done

In the command output, check the Use column to determine the used disk percentage on that node.

Example output

elasticsearch-cdm-kcrsda6l-1-586cc95d4f-h8zq8
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme1n1     19G  522M   19G   3% /elasticsearch/persistent
elasticsearch-cdm-kcrsda6l-2-5b548fc7b-cwwk7
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme2n1     19G  522M   19G   3% /elasticsearch/persistent
elasticsearch-cdm-kcrsda6l-3-5dfc884d99-59tjw
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme3n1     19G  528M   19G   3% /elasticsearch/persistent

If the used disk percentage is above 85%, the node has exceeded the low watermark, and shards can no longer be allocated to this node.

To check the current redundancyPolicy, run the following command:
```
$ oc -n openshift-logging get es elasticsearch \
  -o jsonpath='{.spec.redundancyPolicy}'
```
If you are using a ClusterLogging resource on your cluster, run the following command:
```
$ oc -n openshift-logging get cl \
  -o jsonpath='{.items[*].spec.logStore.elasticsearch.redundancyPolicy}'
```
If the cluster redundancyPolicy value is higher than the SingleRedundancy value, set it to the SingleRedundancy value and save this change.
If the preceding steps do not fix the issue, delete the old indices.
1. Check the status of all indices on Elasticsearch by running the following command:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME -- indices
```
2. Identify an old index that can be deleted.
3. Delete the index by running the following command:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=<elasticsearch_index_name> -X DELETE
```

5.3.4. Elasticsearch node disk high watermark reached

Elasticsearch attempts to relocate shards away from a node that has reached the high watermark to a node with low disk usage that has not crossed any watermark threshold limits.

To allocate shards to a particular node, you must free up some space on that node. If increasing the disk space is not possible, try adding a new data node to the cluster, or decrease the total cluster redundancy policy.

Tip

You can list the available Elasticsearch pods by running the following command:

$ oc -n openshift-logging get pods -l component=elasticsearch

Choose one of the pods listed and set the $ES_POD_NAME variable, by running the following command:

$ export ES_POD_NAME=<elasticsearch_pod_name>

You can now use the $ES_POD_NAME variable in commands.

Procedure

Identify the node on which Elasticsearch is deployed by running the following command:
```
$ oc -n openshift-logging get po -o wide
```

Check the disk space on each node:

$ for pod in `oc -n openshift-logging get po -l component=elasticsearch -o jsonpath='{.items[*].metadata.name}'`; \
  do echo $pod; oc -n openshift-logging exec -c elasticsearch $pod \
  -- df -h /elasticsearch/persistent; done

Check if the cluster is rebalancing:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_cluster/health?pretty | grep relocating_shards
```
If the command output shows relocating shards, the high watermark has been exceeded. The default value of the high watermark is 90%.
Increase the disk space on all nodes. If increasing the disk space is not possible, try adding a new data node to the cluster, or decrease the total cluster redundancy policy.
To check the current redundancyPolicy, run the following command:
```
$ oc -n openshift-logging get es elasticsearch \
  -o jsonpath='{.spec.redundancyPolicy}'
```
If you are using a ClusterLogging resource on your cluster, run the following command:
```
$ oc -n openshift-logging get cl \
  -o jsonpath='{.items[*].spec.logStore.elasticsearch.redundancyPolicy}'
```
If the cluster redundancyPolicy value is higher than the SingleRedundancy value, set it to the SingleRedundancy value and save this change.
If the preceding steps do not fix the issue, delete the old indices.
1. Check the status of all indices on Elasticsearch by running the following command:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME -- indices
```
2. Identify an old index that can be deleted.
3. Delete the index by running the following command:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=<elasticsearch_index_name> -X DELETE
```

5.3.5. Elasticsearch node disk flood watermark reached

Elasticsearch enforces a read-only index block on every index that has both of these conditions:

One or more shards are allocated to the node.
One or more disks exceed the flood stage.

Use the following procedure to troubleshoot this alert.

Tip

You can list the available Elasticsearch pods by running the following command:

$ oc -n openshift-logging get pods -l component=elasticsearch

Choose one of the pods listed and set the $ES_POD_NAME variable, by running the following command:

$ export ES_POD_NAME=<elasticsearch_pod_name>

You can now use the $ES_POD_NAME variable in commands.

Procedure

Get the disk space of the Elasticsearch node:

$ for pod in `oc -n openshift-logging get po -l component=elasticsearch -o jsonpath='{.items[*].metadata.name}'`; \
  do echo $pod; oc -n openshift-logging exec -c elasticsearch $pod \
  -- df -h /elasticsearch/persistent; done

In the command output, check the Avail column to determine the free disk space on that node.

Example output

elasticsearch-cdm-kcrsda6l-1-586cc95d4f-h8zq8
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme1n1     19G  522M   19G   3% /elasticsearch/persistent
elasticsearch-cdm-kcrsda6l-2-5b548fc7b-cwwk7
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme2n1     19G  522M   19G   3% /elasticsearch/persistent
elasticsearch-cdm-kcrsda6l-3-5dfc884d99-59tjw
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme3n1     19G  528M   19G   3% /elasticsearch/persistent

Increase the disk space on all nodes. If increasing the disk space is not possible, try adding a new data node to the cluster, or decrease the total cluster redundancy policy.
To check the current redundancyPolicy, run the following command:
```
$ oc -n openshift-logging get es elasticsearch \
  -o jsonpath='{.spec.redundancyPolicy}'
```
If you are using a ClusterLogging resource on your cluster, run the following command:
```
$ oc -n openshift-logging get cl \
  -o jsonpath='{.items[*].spec.logStore.elasticsearch.redundancyPolicy}'
```
If the cluster redundancyPolicy value is higher than the SingleRedundancy value, set it to the SingleRedundancy value and save this change.
If the preceding steps do not fix the issue, delete the old indices.
1. Check the status of all indices on Elasticsearch by running the following command:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME -- indices
```
2. Identify an old index that can be deleted.
3. Delete the index by running the following command:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=<elasticsearch_index_name> -X DELETE
```

Continue freeing up and monitoring the disk space. After the used disk space drops below 90%, unblock writing to this node by running the following command:

$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=_all/_settings?pretty \
  -X PUT -d '{"index.blocks.read_only_allow_delete": null}'

5.3.6. Elasticsearch JVM heap usage is high

The Elasticsearch node Java virtual machine (JVM) heap memory used is above 75%. Consider increasing the heap size.

5.3.7. Aggregated logging system CPU is high

System CPU usage on the node is high. Check the CPU of the cluster node. Consider allocating more CPU resources to the node.

5.3.8. Elasticsearch process CPU is high

Elasticsearch process CPU usage on the node is high. Check the CPU of the cluster node. Consider allocating more CPU resources to the node.

5.3.9. Elasticsearch disk space is running low

Elasticsearch is predicted to run out of disk space within the next 6 hours based on current disk usage. Use the following procedure to troubleshoot this alert.

Procedure

Get the disk space of the Elasticsearch node:

$ for pod in `oc -n openshift-logging get po -l component=elasticsearch -o jsonpath='{.items[*].metadata.name}'`; \
  do echo $pod; oc -n openshift-logging exec -c elasticsearch $pod \
  -- df -h /elasticsearch/persistent; done

In the command output, check the Avail column to determine the free disk space on that node.

Example output

elasticsearch-cdm-kcrsda6l-1-586cc95d4f-h8zq8
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme1n1     19G  522M   19G   3% /elasticsearch/persistent
elasticsearch-cdm-kcrsda6l-2-5b548fc7b-cwwk7
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme2n1     19G  522M   19G   3% /elasticsearch/persistent
elasticsearch-cdm-kcrsda6l-3-5dfc884d99-59tjw
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme3n1     19G  528M   19G   3% /elasticsearch/persistent

Increase the disk space on all nodes. If increasing the disk space is not possible, try adding a new data node to the cluster, or decrease the total cluster redundancy policy.
To check the current redundancyPolicy, run the following command:
```
$ oc -n openshift-logging get es elasticsearch -o jsonpath='{.spec.redundancyPolicy}'
```
If you are using a ClusterLogging resource on your cluster, run the following command:
```
$ oc -n openshift-logging get cl \
  -o jsonpath='{.items[*].spec.logStore.elasticsearch.redundancyPolicy}'
```
If the cluster redundancyPolicy value is higher than the SingleRedundancy value, set it to the SingleRedundancy value and save this change.
If the preceding steps do not fix the issue, delete the old indices.
1. Check the status of all indices on Elasticsearch by running the following command:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME -- indices
```
2. Identify an old index that can be deleted.
3. Delete the index by running the following command:
```
$ oc exec -n openshift-logging -c elasticsearch $ES_POD_NAME \
  -- es_util --query=<elasticsearch_index_name> -X DELETE
```

Additional resources

Fix a red or yellow cluster status

5.3.10. Elasticsearch FileDescriptor usage is high

Based on current usage trends, the predicted number of file descriptors on the node is insufficient. Check the value of max_file_descriptors for each node as described in the Elasticsearch File Descriptors documentation.

5.4. Viewing the status of the Elasticsearch log store

You can view the status of the OpenShift Elasticsearch Operator and for a number of Elasticsearch components.

5.4.1. Viewing the status of the Elasticsearch log store

You can view the status of the Elasticsearch log store.

Prerequisites

The Red Hat OpenShift Logging Operator and OpenShift Elasticsearch Operator are installed.

Procedure

Change to the openshift-logging project by running the following command:
```
$ oc project openshift-logging
```

To view the status:

Get the name of the Elasticsearch log store instance by running the following command:
```
$ oc get Elasticsearch
```
Example output
```
NAME            AGE
elasticsearch   5h9m
```

Get the Elasticsearch log store status by running the following command:

$ oc get Elasticsearch <Elasticsearch-instance> -o yaml

For example:

$ oc get Elasticsearch elasticsearch -n openshift-logging -o yaml

The output includes information similar to the following:

Example output

status: 1
  cluster: 2
    activePrimaryShards: 30
    activeShards: 60
    initializingShards: 0
    numDataNodes: 3
    numNodes: 3
    pendingTasks: 0
    relocatingShards: 0
    status: green
    unassignedShards: 0
  clusterHealth: ""
  conditions: [] 3
  nodes: 4
  - deploymentName: elasticsearch-cdm-zjf34ved-1
    upgradeStatus: {}
  - deploymentName: elasticsearch-cdm-zjf34ved-2
    upgradeStatus: {}
  - deploymentName: elasticsearch-cdm-zjf34ved-3
    upgradeStatus: {}
  pods: 5
    client:
      failed: []
      notReady: []
      ready:
      - elasticsearch-cdm-zjf34ved-1-6d7fbf844f-sn422
      - elasticsearch-cdm-zjf34ved-2-dfbd988bc-qkzjz
      - elasticsearch-cdm-zjf34ved-3-c8f566f7c-t7zkt
    data:
      failed: []
      notReady: []
      ready:
      - elasticsearch-cdm-zjf34ved-1-6d7fbf844f-sn422
      - elasticsearch-cdm-zjf34ved-2-dfbd988bc-qkzjz
      - elasticsearch-cdm-zjf34ved-3-c8f566f7c-t7zkt
    master:
      failed: []
      notReady: []
      ready:
      - elasticsearch-cdm-zjf34ved-1-6d7fbf844f-sn422
      - elasticsearch-cdm-zjf34ved-2-dfbd988bc-qkzjz
      - elasticsearch-cdm-zjf34ved-3-c8f566f7c-t7zkt
  shardAllocationEnabled: all

1

In the output, the cluster status fields appear in the status stanza.

2

The status of the Elasticsearch log store:

The number of active primary shards.
The number of active shards.
The number of shards that are initializing.
The number of Elasticsearch log store data nodes.
The total number of Elasticsearch log store nodes.
The number of pending tasks.
The Elasticsearch log store status: green, red, yellow.
The number of unassigned shards.

3

Any status conditions, if present. The Elasticsearch log store status indicates the reasons from the scheduler if a pod could not be placed. Any events related to the following conditions are shown:

Container Waiting for both the Elasticsearch log store and proxy containers.
Container Terminated for both the Elasticsearch log store and proxy containers.
Pod unschedulable. Also, a condition is shown for a number of issues; see Example condition messages.

4

The Elasticsearch log store nodes in the cluster, with upgradeStatus.

5

The Elasticsearch log store client, data, and master pods in the cluster, listed under failed, notReady, or ready state.

5.4.1.1. Example condition messages

The following are examples of some condition messages from the Status section of the Elasticsearch instance.

The following status message indicates that a node has exceeded the configured low watermark, and no shard will be allocated to this node.

status:
  nodes:
  - conditions:
    - lastTransitionTime: 2019-03-15T15:57:22Z
      message: Disk storage usage for node is 27.5gb (36.74%). Shards will be not
        be allocated on this node.
      reason: Disk Watermark Low
      status: "True"
      type: NodeStorage
    deploymentName: example-elasticsearch-cdm-0-1
    upgradeStatus: {}

The following status message indicates that a node has exceeded the configured high watermark, and shards will be relocated to other nodes.

status:
  nodes:
  - conditions:
    - lastTransitionTime: 2019-03-15T16:04:45Z
      message: Disk storage usage for node is 27.5gb (36.74%). Shards will be relocated
        from this node.
      reason: Disk Watermark High
      status: "True"
      type: NodeStorage
    deploymentName: example-elasticsearch-cdm-0-1
    upgradeStatus: {}

The following status message indicates that the Elasticsearch log store node selector in the custom resource (CR) does not match any nodes in the cluster:

status:
    nodes:
    - conditions:
      - lastTransitionTime: 2019-04-10T02:26:24Z
        message: '0/8 nodes are available: 8 node(s) didn''t match node selector.'
        reason: Unschedulable
        status: "True"
        type: Unschedulable

The following status message indicates that the Elasticsearch log store CR uses a non-existent persistent volume claim (PVC).

status:
   nodes:
   - conditions:
     - last Transition Time:  2019-04-10T05:55:51Z
       message:               pod has unbound immediate PersistentVolumeClaims (repeated 5 times)
       reason:                Unschedulable
       status:                True
       type:                  Unschedulable

The following status message indicates that your Elasticsearch log store cluster does not have enough nodes to support the redundancy policy.

status:
  clusterHealth: ""
  conditions:
  - lastTransitionTime: 2019-04-17T20:01:31Z
    message: Wrong RedundancyPolicy selected. Choose different RedundancyPolicy or
      add more nodes with data roles
    reason: Invalid Settings
    status: "True"
    type: InvalidRedundancy

This status message indicates your cluster has too many control plane nodes:

status:
  clusterHealth: green
  conditions:
    - lastTransitionTime: '2019-04-17T20:12:34Z'
      message: >-
        Invalid master nodes count. Please ensure there are no more than 3 total
        nodes with master roles
      reason: Invalid Settings
      status: 'True'
      type: InvalidMasters

The following status message indicates that Elasticsearch storage does not support the change you tried to make.

For example:

status:
  clusterHealth: green
  conditions:
    - lastTransitionTime: "2021-05-07T01:05:13Z"
      message: Changing the storage structure for a custom resource is not supported
      reason: StorageStructureChangeIgnored
      status: 'True'
      type: StorageStructureChangeIgnored

The reason and type fields specify the type of unsupported change:

StorageClassNameChangeIgnored: Unsupported change to the storage class name.
StorageSizeChangeIgnored: Unsupported change the storage size.
StorageStructureChangeIgnored: Unsupported change between ephemeral and persistent storage structures.
Important
If you try to configure the ClusterLogging CR to switch from ephemeral to persistent storage, the OpenShift Elasticsearch Operator creates a persistent volume claim (PVC) but does not create a persistent volume (PV). To clear the StorageStructureChangeIgnored status, you must revert the change to the ClusterLogging CR and delete the PVC.

5.4.2. Viewing the status of the log store components

You can view the status for a number of the log store components.

Elasticsearch indices

You can view the status of the Elasticsearch indices.

Get the name of an Elasticsearch pod:

$ oc get pods --selector component=elasticsearch -o name

Example output

pod/elasticsearch-cdm-1godmszn-1-6f8495-vp4lw
pod/elasticsearch-cdm-1godmszn-2-5769cf-9ms2n
pod/elasticsearch-cdm-1godmszn-3-f66f7d-zqkz7

Get the status of the indices:

$ oc exec elasticsearch-cdm-4vjor49p-2-6d4d7db474-q2w7z -- indices

Example output

Defaulting container name to elasticsearch.
Use 'oc describe pod/elasticsearch-cdm-4vjor49p-2-6d4d7db474-q2w7z -n openshift-logging' to see all of the containers in this pod.

green  open   infra-000002                                                     S4QANnf1QP6NgCegfnrnbQ   3   1     119926            0        157             78
green  open   audit-000001                                                     8_EQx77iQCSTzFOXtxRqFw   3   1          0            0          0              0
green  open   .security                                                        iDjscH7aSUGhIdq0LheLBQ   1   1          5            0          0              0
green  open   .kibana_-377444158_kubeadmin                                     yBywZ9GfSrKebz5gWBZbjw   3   1          1            0          0              0
green  open   infra-000001                                                     z6Dpe__ORgiopEpW6Yl44A   3   1     871000            0        874            436
green  open   app-000001                                                       hIrazQCeSISewG3c2VIvsQ   3   1       2453            0          3              1
green  open   .kibana_1                                                        JCitcBMSQxKOvIq6iQW6wg   1   1          0            0          0              0
green  open   .kibana_-1595131456_user1                                        gIYFIEGRRe-ka0W3okS-mQ   3   1          1            0          0              0

Log store pods

You can view the status of the pods that host the log store.

Get the name of a pod:

$ oc get pods --selector component=elasticsearch -o name

Example output

pod/elasticsearch-cdm-1godmszn-1-6f8495-vp4lw
pod/elasticsearch-cdm-1godmszn-2-5769cf-9ms2n
pod/elasticsearch-cdm-1godmszn-3-f66f7d-zqkz7

Get the status of a pod:

$ oc describe pod elasticsearch-cdm-1godmszn-1-6f8495-vp4lw

The output includes the following status information:

Example output

....
Status:             Running

....

Containers:
  elasticsearch:
    Container ID:   cri-o://b7d44e0a9ea486e27f47763f5bb4c39dfd2
    State:          Running
      Started:      Mon, 08 Jun 2020 10:17:56 -0400
    Ready:          True
    Restart Count:  0
    Readiness:  exec [/usr/share/elasticsearch/probe/readiness.sh] delay=10s timeout=30s period=5s #success=1 #failure=3

....

  proxy:
    Container ID:  cri-o://3f77032abaddbb1652c116278652908dc01860320b8a4e741d06894b2f8f9aa1
    State:          Running
      Started:      Mon, 08 Jun 2020 10:18:38 -0400
    Ready:          True
    Restart Count:  0

....

Conditions:
  Type              Status
  Initialized       True
  Ready             True
  ContainersReady   True
  PodScheduled      True

....

Events:          <none>

Log storage pod deployment configuration

You can view the status of the log store deployment configuration.

Get the name of a deployment configuration:

$ oc get deployment --selector component=elasticsearch -o name

Example output

deployment.extensions/elasticsearch-cdm-1gon-1
deployment.extensions/elasticsearch-cdm-1gon-2
deployment.extensions/elasticsearch-cdm-1gon-3

Get the deployment configuration status:

$ oc describe deployment elasticsearch-cdm-1gon-1

The output includes the following status information:

Example output

....
  Containers:
   elasticsearch:
    Image:      registry.redhat.io/openshift-logging/elasticsearch6-rhel8
    Readiness:  exec [/usr/share/elasticsearch/probe/readiness.sh] delay=10s timeout=30s period=5s #success=1 #failure=3

....

Conditions:
  Type           Status   Reason
  ----           ------   ------
  Progressing    Unknown  DeploymentPaused
  Available      True     MinimumReplicasAvailable

....

Events:          <none>

Log store replica set

You can view the status of the log store replica set.

Get the name of a replica set:

$ oc get replicaSet --selector component=elasticsearch -o name

replicaset.extensions/elasticsearch-cdm-1gon-1-6f8495
replicaset.extensions/elasticsearch-cdm-1gon-2-5769cf
replicaset.extensions/elasticsearch-cdm-1gon-3-f66f7d

Get the status of the replica set:

$ oc describe replicaSet elasticsearch-cdm-1gon-1-6f8495

The output includes the following status information:

Example output

....
  Containers:
   elasticsearch:
    Image:      registry.redhat.io/openshift-logging/elasticsearch6-rhel8@sha256:4265742c7cdd85359140e2d7d703e4311b6497eec7676957f455d6908e7b1c25
    Readiness:  exec [/usr/share/elasticsearch/probe/readiness.sh] delay=10s timeout=30s period=5s #success=1 #failure=3

....

Events:          <none>

5.4.3. Elasticsearch cluster status

A dashboard in the Observe section of the OpenShift Container Platform web console displays the status of the Elasticsearch cluster.

To get the status of the OpenShift Elasticsearch cluster, visit the dashboard in the Observe section of the OpenShift Container Platform web console at <cluster_url>/monitoring/dashboards/grafana-dashboard-cluster-logging.

Elasticsearch status fields

eo_elasticsearch_cr_cluster_management_state

Shows whether the Elasticsearch cluster is in a managed or unmanaged state. For example:

eo_elasticsearch_cr_cluster_management_state{state="managed"} 1
eo_elasticsearch_cr_cluster_management_state{state="unmanaged"} 0

eo_elasticsearch_cr_restart_total

Shows the number of times the Elasticsearch nodes have restarted for certificate restarts, rolling restarts, or scheduled restarts. For example:

eo_elasticsearch_cr_restart_total{reason="cert_restart"} 1
eo_elasticsearch_cr_restart_total{reason="rolling_restart"} 1
eo_elasticsearch_cr_restart_total{reason="scheduled_restart"} 3

es_index_namespaces_total

Shows the total number of Elasticsearch index namespaces. For example:

Total number of Namespaces.
es_index_namespaces_total 5

es_index_document_count

Shows the number of records for each namespace. For example:

es_index_document_count{namespace="namespace_1"} 25
es_index_document_count{namespace="namespace_2"} 10
es_index_document_count{namespace="namespace_3"} 5

The "Secret Elasticsearch fields are either missing or empty" message

If Elasticsearch is missing the admin-cert, admin-key, logging-es.crt, or logging-es.key files, the dashboard shows a status message similar to the following example:

message": "Secret \"elasticsearch\" fields are either missing or empty: [admin-cert, admin-key, logging-es.crt, logging-es.key]",
"reason": "Missing Required Secrets",

Chapter 5. Troubleshooting logging

5.1. Viewing Logging status

5.1.1. Viewing the status of the Red Hat OpenShift Logging Operator

5.1.1.1. Example condition messages

5.1.2. Viewing the status of logging components

5.2. Troubleshooting log forwarding

5.2.1. Redeploying Fluentd pods

5.2.2. Troubleshooting Loki rate limit errors

5.3. Troubleshooting logging alerts

5.3.1. Elasticsearch cluster health status is red

5.3.2. Elasticsearch cluster health status is yellow

5.3.3. Elasticsearch node disk low watermark reached

5.3.4. Elasticsearch node disk high watermark reached

5.3.5. Elasticsearch node disk flood watermark reached

5.3.6. Elasticsearch JVM heap usage is high

5.3.7. Aggregated logging system CPU is high

5.3.8. Elasticsearch process CPU is high

5.3.9. Elasticsearch disk space is running low

5.3.10. Elasticsearch FileDescriptor usage is high

5.4. Viewing the status of the Elasticsearch log store

5.4.1. Viewing the status of the Elasticsearch log store

5.4.1.1. Example condition messages

5.4.2. Viewing the status of the log store components

5.4.3. Elasticsearch cluster status

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