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Chapter 18. Load balancing on RHOSP

18.1. Using the Octavia OVN load balancer provider driver with Kuryr SDN

If your OpenShift Container Platform cluster uses Kuryr and was installed on a Red Hat OpenStack Platform (RHOSP) 13 cloud that was later upgraded to RHOSP 16, you can configure it to use the Octavia OVN provider driver.

Important

Kuryr replaces existing load balancers after you change provider drivers. This process results in some downtime.

Prerequisites

  • Install the RHOSP CLI, openstack.
  • Install the OpenShift Container Platform CLI, oc.

  • Verify that the Octavia OVN driver on RHOSP is enabled.

    Tip

    To view a list of available Octavia drivers, on a command line, enter openstack loadbalancer provider list.

    The ovn driver is displayed in the command’s output.

Procedure

To change from the Octavia Amphora provider driver to Octavia OVN:

  1. Open the kuryr-config ConfigMap. On a command line, enter: 

    $ oc -n openshift-kuryr edit cm kuryr-config

  2. In the ConfigMap, delete the line that contains kuryr-octavia-provider: default. For example: 

    ...
kind: ConfigMap
metadata:
  annotations:
    networkoperator.openshift.io/kuryr-octavia-provider: default 1
...
    1
    Delete this line. The cluster will regenerate it with ovn as the value.

    Wait for the Cluster Network Operator to detect the modification and to redeploy the kuryr-controller and kuryr-cni pods. This process might take several minutes.

  3. Verify that the kuryr-config ConfigMap annotation is present with ovn as its value. On a command line, enter: 

    $ oc -n openshift-kuryr edit cm kuryr-config

    The ovn provider value is displayed in the output: 

    ...
kind: ConfigMap
metadata:
  annotations:
    networkoperator.openshift.io/kuryr-octavia-provider: ovn
...

  4. Verify that RHOSP recreated its load balancers.

    1. On a command line, enter: 

      $ openstack loadbalancer list | grep amphora

      A single Amphora load balancer is displayed. For example: 

      a4db683b-2b7b-4988-a582-c39daaad7981 | ostest-7mbj6-kuryr-api-loadbalancer  | 84c99c906edd475ba19478a9a6690efd | 172.30.0.1     | ACTIVE              | amphora

    2. Search for ovn load balancers by entering: 

      $ openstack loadbalancer list | grep ovn

      The remaining load balancers of the ovn type are displayed. For example: 

      2dffe783-98ae-4048-98d0-32aa684664cc | openshift-apiserver-operator/metrics | 84c99c906edd475ba19478a9a6690efd | 172.30.167.119 | ACTIVE              | ovn
0b1b2193-251f-4243-af39-2f99b29d18c5 | openshift-etcd/etcd                  | 84c99c906edd475ba19478a9a6690efd | 172.30.143.226 | ACTIVE              | ovn
f05b07fc-01b7-4673-bd4d-adaa4391458e | openshift-dns-operator/metrics       | 84c99c906edd475ba19478a9a6690efd | 172.30.152.27  | ACTIVE              | ovn

18.2. Scaling clusters for application traffic by using Octavia

OpenShift Container Platform clusters that run on Red Hat OpenStack Platform (RHOSP) can use the Octavia load balancing service to distribute traffic across multiple virtual machines (VMs) or floating IP addresses. This feature mitigates the bottleneck that single machines or addresses create.

If your cluster uses Kuryr, the Cluster Network Operator created an internal Octavia load balancer at deployment. You can use this load balancer for application network scaling.

If your cluster does not use Kuryr, you must create your own Octavia load balancer to use it for application network scaling.

18.2.1. Scaling clusters by using Octavia

If you want to use multiple API load balancers, or if your cluster does not use Kuryr, create an Octavia load balancer and then configure your cluster to use it.

Prerequisites

  • Octavia is available on your Red Hat OpenStack Platform (RHOSP) deployment.

Procedure

  1. From a command line, create an Octavia load balancer that uses the Amphora driver: 

    $ openstack loadbalancer create --name API_OCP_CLUSTER --vip-subnet-id <id_of_worker_vms_subnet>

    You can use a name of your choice instead of API_OCP_CLUSTER.

  2. After the load balancer becomes active, create listeners: 

    $ openstack loadbalancer listener create --name API_OCP_CLUSTER_6443 --protocol HTTPS--protocol-port 6443 API_OCP_CLUSTER
    Note

    To view the status of the load balancer, enter openstack loadbalancer list.

  3. Create a pool that uses the round robin algorithm and has session persistence enabled: 

    $ openstack loadbalancer pool create --name API_OCP_CLUSTER_pool_6443 --lb-algorithm ROUND_ROBIN --session-persistence type=<source_IP_address> --listener API_OCP_CLUSTER_6443 --protocol HTTPS

  4. To ensure that control plane machines are available, create a health monitor: 

    $ openstack loadbalancer healthmonitor create --delay 5 --max-retries 4 --timeout 10 --type TCP API_OCP_CLUSTER_pool_6443

  5. Add the control plane machines as members of the load balancer pool: 

    $ for SERVER in $(MASTER-0-IP MASTER-1-IP MASTER-2-IP)
do
  openstack loadbalancer member create --address $SERVER  --protocol-port 6443 API_OCP_CLUSTER_pool_6443
done

  6. Optional: To reuse the cluster API floating IP address, unset it: 

    $ openstack floating ip unset $API_FIP

  7. Add either the unset API_FIP or a new address to the created load balancer VIP: 

    $ openstack floating ip set  --port $(openstack loadbalancer show -c <vip_port_id> -f value API_OCP_CLUSTER) $API_FIP

Your cluster now uses Octavia for load balancing.

Note

If Kuryr uses the Octavia Amphora driver, all traffic is routed through a single Amphora virtual machine (VM).

You can repeat this procedure to create additional load balancers, which can alleviate the bottleneck.

18.2.2. Scaling clusters that use Kuryr by using Octavia

If your cluster uses Kuryr, associate the API floating IP address of your cluster with the pre-existing Octavia load balancer.

Prerequisites

  • Your OpenShift Container Platform cluster uses Kuryr.
  • Octavia is available on your Red Hat OpenStack Platform (RHOSP) deployment.

Procedure

  1. Optional: From a command line, to reuse the cluster API floating IP address, unset it: 

    $ openstack floating ip unset $API_FIP

  2. Add either the unset API_FIP or a new address to the created load balancer VIP: 

    $ openstack floating ip set --port $(openstack loadbalancer show -c <vip_port_id> -f value ${OCP_CLUSTER}-kuryr-api-loadbalancer) $API_FIP

Your cluster now uses Octavia for load balancing.

Note

If Kuryr uses the Octavia Amphora driver, all traffic is routed through a single Amphora virtual machine (VM).

You can repeat this procedure to create additional load balancers, which can alleviate the bottleneck.

18.3. Scaling for ingress traffic by using RHOSP Octavia

You can use Octavia load balancers to scale Ingress controllers on clusters that use Kuryr.

Prerequisites

  • Your OpenShift Container Platform cluster uses Kuryr.
  • Octavia is available on your RHOSP deployment.

Procedure

  1. To copy the current internal router service, on a command line, enter: 

    $ oc -n openshift-ingress get svc router-internal-default -o yaml > external_router.yaml

  2. In the file external_router.yaml, change the values of metadata.name and spec.type to LoadBalancer.

    Example router file

    apiVersion: v1
kind: Service
metadata:
  labels:
    ingresscontroller.operator.openshift.io/owning-ingresscontroller: default
  name: router-external-default 1
  namespace: openshift-ingress
spec:
  ports:
  - name: http
    port: 80
    protocol: TCP
    targetPort: http
  - name: https
    port: 443
    protocol: TCP
    targetPort: https
  - name: metrics
    port: 1936
    protocol: TCP
    targetPort: 1936
  selector:
    ingresscontroller.operator.openshift.io/deployment-ingresscontroller: default
  sessionAffinity: None
  type: LoadBalancer 2

    1
    Ensure that this value is descriptive, like router-external-default.
    2
    Ensure that this value is LoadBalancer.
Note

You can delete timestamps and other information that is irrelevant to load balancing.

  1. From a command line, create a service from the external_router.yaml file: 

    $ oc apply -f external_router.yaml

  2. Verify that the external IP address of the service is the same as the one that is associated with the load balancer:

    1. On a command line, retrieve the external IP address of the service: 

      $ oc -n openshift-ingress get svc

      Example output

      NAME                      TYPE           CLUSTER-IP       EXTERNAL-IP    PORT(S)                                     AGE
router-external-default   LoadBalancer   172.30.235.33    10.46.22.161   80:30112/TCP,443:32359/TCP,1936:30317/TCP   3m38s
router-internal-default   ClusterIP      172.30.115.123   <none>         80/TCP,443/TCP,1936/TCP                     22h

    2. Retrieve the IP address of the load balancer: 

      $ openstack loadbalancer list | grep router-external

      Example output

      | 21bf6afe-b498-4a16-a958-3229e83c002c | openshift-ingress/router-external-default | 66f3816acf1b431691b8d132cc9d793c | 172.30.235.33  | ACTIVE | octavia |

    3. Verify that the addresses you retrieved in the previous steps are associated with each other in the floating IP list: 

      $ openstack floating ip list | grep 172.30.235.33

      Example output

      | e2f80e97-8266-4b69-8636-e58bacf1879e | 10.46.22.161 | 172.30.235.33 | 655e7122-806a-4e0a-a104-220c6e17bda6 | a565e55a-99e7-4d15-b4df-f9d7ee8c9deb | 66f3816acf1b431691b8d132cc9d793c |

You can now use the value of EXTERNAL-IP as the new Ingress address.

Note

If Kuryr uses the Octavia Amphora driver, all traffic is routed through a single Amphora virtual machine (VM).

You can repeat this procedure to create additional load balancers, which can alleviate the bottleneck.

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