Note, this page is based on the SDNC-C Clustering on Kubernetes page as created by Beili Zhou.

About the APPC-C Clustering

The following pod layout is desired for the APPC cluster deployment (as described in  APPC-476 - Getting issue details... STATUS ) from POD and SERVICE view, which will have:

• 1 DB pod (2 or more DB pods to supported with the introduction of MariaDB and Galera)
• 3 appc (ODL) pods
• 1 dgbuilder pod
• 1 cdt pod

APPC DB Clustering details

See details from APPC DB (MySQL) Clustered Deployment.

Deployment Setup Steps

You can use Rancher or kubeadm to deploy your Kubernetes cluster:

• Deployment with Kubernetes Cluster Configured by Rancher or
• Deploying Kubernetes Cluster with kubeadm

Additional Information

APPC Startup Order

Troubleshoot situation where APPC pods do not start up in order

Usually, this is caused by init-container malfuntion. You can troubleshoot it by the following steps:

• Do a describe of the pod using command kubectl describe pod <pod-name>, to ensure the Init Container section is presented as your defined in your yaml template.

• If it does not exist, it is possible that your Kubernetes version supports a different format for the init-containers:

  init-containers syntax supported by Kubernetes 1.5, 1.6 and 1.7 and not supported by Kubernetes 1.8 and greater

  initContainers syntax supported from Kubernetes 1.6 and greater

  Init container is defined under spec.template.metadata.annotations."pod.beta.kubernetes.io/init-containers An example of init container by beta annotation Expand source apiVersion: apps/v1beta1 kind: StatefulSet metadata: name: appc ... spec: ... template: metadata: ... annotations: pod.beta.kubernetes.io/init-containers: '[ { "args": [ "--container-name", "appc-db-container" ], "command": [ "/root/ready.py" ], "env": [ { "name": "NAMESPACE", "valueFrom": { "fieldRef": { "apiVersion": "v1", "fieldPath": "metadata.namespace" } } } ], "image": "{{ .Values.image.readiness }}", "imagePullPolicy": "{{ .Values.pullPolicy }}", "name": "appc-readiness" } ]' spec: containers: ...

  Init container is defined under spec.template.spec.initContainers An example of init container by spec.initContainers Expand source apiVersion: apps/v1beta1 kind: StatefulSet metadata: name: sdnc ... spec: ... template: ... spec: initContainers: - command: - /root/ready.py - "--container-name" - "appc-db-container" env: - name: NAMESPACE valueFrom: fieldRef: apiVersion: v1 fieldPath: metadata.namespace image: "{{ .Values.image.readiness }}" imagePullPolicy: {{ .Values.pullPolicy }} name: appc-readiness containers: ...

Restart Dead Instance (start a new one in its place)

When a pod is dead, Kubernetes automatically starts a new one to replace the dead pod.

Examples:

• Pod-level restart:

• Container-level restart: