Chapter 10. Configuring your Logging deployment

Procedure

1. Edit the ClusterLogging custom resource (CR) in the openshift-logging project:

   $ oc -n openshift-logging edit ClusterLogging instance

   apiVersion: "logging.openshift.io/v1"
   kind: "ClusterLogging"
   metadata:
     name: "instance"
     namespace: openshift-logging
   
   ...
   
   spec:
     managementState: "Managed"
     logStore:
       type: "elasticsearch"
       elasticsearch:
         nodeCount: 3
         resources: 1
           limits:
             memory: 16Gi
           requests:
             cpu: 200m
             memory: 16Gi
         storage:
           storageClassName: "gp2"
           size: "200G"
         redundancyPolicy: "SingleRedundancy"
     visualization:
       type: "kibana"
       kibana:
         resources: 2
           limits:
             memory: 1Gi
           requests:
             cpu: 500m
             memory: 1Gi
         proxy:
           resources: 3
             limits:
               memory: 100Mi
             requests:
               cpu: 100m
               memory: 100Mi
         replicas: 2
     collection:
       resources: 4
         limits:
           memory: 736Mi
         requests:
           cpu: 200m
           memory: 736Mi
       type: fluentd

   1

   Specify the CPU and memory limits and requests for the log store as needed. For Elasticsearch, you must adjust both the request value and the limit value.

   2 3

   Specify the CPU and memory limits and requests for the log visualizer as needed.

   4

   Specify the CPU and memory limits and requests for the log collector as needed.

Procedure

1. Create a Butane config file, 40-worker-custom-journald.bu, that includes an /etc/systemd/journald.conf file with the required settings.

   Note

   See "Creating machine configs with Butane" for information about Butane.

   variant: openshift
   version: 4.16.0
   metadata:
     name: 40-worker-custom-journald
     labels:
       machineconfiguration.openshift.io/role: "worker"
   storage:
     files:
     - path: /etc/systemd/journald.conf
       mode: 0644 1
       overwrite: true
       contents:
         inline: |
           Compress=yes 2
           ForwardToConsole=no 3
           ForwardToSyslog=no
           MaxRetentionSec=1month 4
           RateLimitBurst=10000 5
           RateLimitIntervalSec=30s
           Storage=persistent 6
           SyncIntervalSec=1s 7
           SystemMaxUse=8G 8
           SystemKeepFree=20% 9
           SystemMaxFileSize=10M 10

   1

   Set the permissions for the journald.conf file. It is recommended to set 0644 permissions.

   2

   Specify whether you want logs compressed before they are written to the file system. Specify yes to compress the message or no to not compress. The default is yes.

   3

   Configure whether to forward log messages. Defaults to no for each. Specify:

   • ForwardToConsole to forward logs to the system console.
   • ForwardToKMsg to forward logs to the kernel log buffer.
   • ForwardToSyslog to forward to a syslog daemon.
   • ForwardToWall to forward messages as wall messages to all logged-in users.

   4

   Specify the maximum time to store journal entries. Enter a number to specify seconds. Or include a unit: "year", "month", "week", "day", "h" or "m". Enter 0 to disable. The default is 1month.

   5

   Configure rate limiting. If more logs are received than what is specified in RateLimitBurst during the time interval defined by RateLimitIntervalSec, all further messages within the interval are dropped until the interval is over. It is recommended to set RateLimitIntervalSec=30s and RateLimitBurst=10000, which are the defaults.

   6

   Specify how logs are stored. The default is persistent:

   • volatile to store logs in memory in /run/log/journal/. These logs are lost after rebooting.
   • persistent to store logs to disk in /var/log/journal/. systemd creates the directory if it does not exist.
   • auto to store logs in /var/log/journal/ if the directory exists. If it does not exist, systemd temporarily stores logs in /run/systemd/journal.
   • none to not store logs. systemd drops all logs.

   7

   Specify the timeout before synchronizing journal files to disk for ERR, WARNING, NOTICE, INFO, and DEBUG logs. systemd immediately syncs after receiving a CRIT, ALERT, or EMERG log. The default is 1s.

   8

   Specify the maximum size the journal can use. The default is 8G.

   9

   Specify how much disk space systemd must leave free. The default is 20%.

   10

   Specify the maximum size for individual journal files stored persistently in /var/log/journal. The default is 10M.

   Note

   If you are removing the rate limit, you might see increased CPU utilization on the system logging daemons as it processes any messages that would have previously been throttled.

   For more information on systemd settings, see https://www.freedesktop.org/software/systemd/man/journald.conf.html. The default settings listed on that page might not apply to OpenShift Container Platform.

2. Use Butane to generate a MachineConfig object file, 40-worker-custom-journald.yaml, containing the configuration to be delivered to the nodes:

   $ butane 40-worker-custom-journald.bu -o 40-worker-custom-journald.yaml

3. Apply the machine config. For example:

   $ oc apply -f 40-worker-custom-journald.yaml

   The controller detects the new MachineConfig object and generates a new rendered-worker-<hash> version.

4. Monitor the status of the rollout of the new rendered configuration to each node:

   $ oc describe machineconfigpool/worker

   Example output

   Name:         worker
   Namespace:
   Labels:       machineconfiguration.openshift.io/mco-built-in=
   Annotations:  <none>
   API Version:  machineconfiguration.openshift.io/v1
   Kind:         MachineConfigPool
   
   ...
   
   Conditions:
     Message:
     Reason:                All nodes are updating to rendered-worker-913514517bcea7c93bd446f4830bc64e