How to use git-sync image as a sidecar in kubernetes that git pulls periodically

Question

I am trying to use git-sync image as a side car in kubernetes that runs git-pull periodically and mounts cloned data to shared volume.

Everything is working fine when I configure it for sync one time. I want to run it periodically like every 10 mins. Somehow when I configure it to run periodically pod initializing is failing.

I read documentation but couldn't find proper answer. Would be nice if you help me to figure out what I am missing in my configuration.

Here is my configuration that failing.

Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: nginx-helloworld
          image: nginx
          ports:
            - containerPort: 80
          volumeMounts:
            - mountPath: "/usr/share/nginx/html"
              name: www-data
      initContainers:
        - name: git-sync
          image: k8s.gcr.io/git-sync:v3.1.3
          volumeMounts:
            - name: www-data
              mountPath: /data
          env:
            - name: GIT_SYNC_REPO
              value: "https://github.com/musaalp/design-patterns.git" ##repo-path-you-want-to-clone
            - name: GIT_SYNC_BRANCH
              value: "master" ##repo-branch
            - name: GIT_SYNC_ROOT
              value: /data
            - name: GIT_SYNC_DEST
              value: "hello" ##path-where-you-want-to-clone
            - name: GIT_SYNC_PERIOD
              value: "10"
            - name: GIT_SYNC_ONE_TIME
              value: "false"
          securityContext:
            runAsUser: 0
      volumes:
        - name: www-data
          emptyDir: {}

Pod

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: nginx-helloworld
  name: nginx-helloworld
spec:
  containers:
  - image: nginx
    name: nginx-helloworld
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Never
status: {}

Adiii · Accepted Answer · 2022-08-22T15:04:38.737

you are using the git-sync as an initContainers, which run only during init (once in lifecycle)

A Pod can have multiple containers running apps within it, but it can also have one or more init containers, which are run before the app containers are started.

Init containers are exactly like regular containers, except:

Init containers always run to completion.

Each init container must complete successfully before the next one starts. init-containers

So use this as a regular container

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: git-sync
          image: k8s.gcr.io/git-sync:v3.1.3
          volumeMounts:
            - name: www-data
              mountPath: /data
          env:
            - name: GIT_SYNC_REPO
              value: "https://github.com/musaalp/design-patterns.git" ##repo-path-you-want-to-clone
            - name: GIT_SYNC_BRANCH
              value: "master" ##repo-branch
            - name: GIT_SYNC_ROOT
              value: /data
            - name: GIT_SYNC_DEST
              value: "hello" ##path-where-you-want-to-clone
            - name: GIT_SYNC_PERIOD
              value: "20"
            - name: GIT_SYNC_ONE_TIME
              value: "false"
          securityContext:
            runAsUser: 0
        - name: nginx-helloworld
          image: nginx
          ports:
            - containerPort: 80
          volumeMounts:
            - mountPath: "/usr/share/nginx/html"
              name: www-data
      volumes:
        - name: www-data
          emptyDir: {}

Thank you, its working as you said as a regular container. I just have another question. I am trying to override sync period by mentioning GIT_SYNC_PERIOD but its not working. I assume its interpreted as second. So value for GIT_SYNC_PERIOD either 45 or 45s didn't work. I basically want git sync every 10min. — Musa, Aug 22 '22 at 15:02
> --period , `$GIT_SYNC_PERIOD` How long to wait between sync attempts. This must be at least 10ms. — Adiii, Aug 22 '22 at 15:04
Actually thats the problem. It always use the default value which is 10ms. I want to override it. — Musa, Aug 22 '22 at 15:06
its here https://stackoverflow.com/questions/73447467/how-to-override-git-sync-sync-period — Musa, Aug 22 '22 at 15:21

How to use git-sync image as a sidecar in kubernetes that git pulls periodically

1 Answers1