Avi Kubernetes Operator 1.13

1.13 1.12 1.11 1.10

High Availability Support in
AKO

This feature allows the user to run two instances of
AKO
 in a Kubernetes/OpenShift cluster, that is, one in active mode and the other in passive mode.
The following describes the high availability architecture of
AKO
:
Active and passive modes are assigned automatically by performing a leadership election among the
AKO
s. A lease lock (Kubernetes object) named
ako-lease-lock
 in the avi-system is used to keep track of the current active
AKO
. The lease lock object has the identity of the current active
AKO
 and a field named renewTime which active
AKO
 periodically refreshes. The passive
AKO
 periodically polls the lease lock object and updates its identity in the lease lock object when the renewTime goes beyond the deadline.
The following describes how the leader election between
AKO
s occurs:
Active
AKO
 does the following:
  • Creates the
    Avi Load Balancer
     objects in the
    Avi Load Balancer Controller
    .
  • Updates the status of the Ingress/Routes/Service of type LB.
  • Cleans up the stale
    Avi Load Balancer
     objects from the
    Avi Load Balancer Controller
    .
  • Cleans up the
    Avi Load Balancer
     objects created by
    AKO
     from the controller when
    deleteConfig
     is set.
  • Creates the lease object in the
    avi-system
     namespace and periodically renews the renewTime of the lease object.
Passive
AKO
 does the following:
  • Polls the lease object in the
    avi-system
     namespace.
  • Reads the objects in Kubernetes/OpenShift cluster and populates the cache.
  • Reads the
    Avi Load Balancer
     objects configured by Active
    AKO
     and builds the cache.

Steps to Run
AKO
 in High Availability

  1. Change the
    replicaCount
     in values.yaml to two.
  2. Execute the helm
    upgrade
     command and provide the updated values.yaml file.
    helm upgrade ako-1593523840
oci://projects.packages.broadcom.com/ako/helm-charts/ako -f /path/to/values.yaml
--version 1.13.1 --set ControllerSettings.controllerHost= --set
avicredentials.password= --set avicredentials.username= --namespace=avi-system
  1. Currently, more than two replicas are not supported.
  2. Both instances of
    AKO
     must be on the same version.

Content feedback and comments