Set timezone in asp.net 6.0 in linux container

July 21, 2022 - 1 minutes read - 189 words

According to many articles one the web, the way to set timezone is as following:

cp /usr/share/zoneinfo/Asia/Singapore /etc/localtime
echo 'Asia/Singapore' > /etc/timezone

You can indeed get the correct time if you run it in dotnet core 5 docker linux containers. However you couldn’t get the correct local time in dotnet 6.0. I found the issue About time incorrect of docker image about aspnet-6 #62545. After I tried serveral combinations mentioned in the issue, finally I got a working solution. Here is my solution.

cp /usr/share/zoneinfo/Asia/Singapore /etc/localtime
echo 'Asia/Singapore' > /etc/timezone
export TZ=Asia/Singapore

In my k8s environemts, I used kustomize to manage yaml resources. To minimize this change, I use a jsonpatch to patch all my relevant deployemnts. Here is my jsonpatch and a fraction of kustomization.yaml.

// filename: tz-patch.json
[
 {
  "op": "add",
  "path": "/spec/template/spec/containers/0/lifecycle",
  "value": {
   "postStart": {
    "exec": {
     "command": [
      "/bin/sh",
      "-c",
      "cp /usr/share/zoneinfo/Asia/Singapore /etc/localtime && echo 'Asia/Singapore' > /etc/timezone"
     ]
    }
   }
  }
 },
 {
    "op": "add",
    "path": "/spec/template/spec/containers/0/env/0",
    "value": {
        "name": "TZ",
        "value": "Asia/Singapore"
    }
}
]

# filename: kustomization.yaml
patches:
- path: tz-patch.json
  target:
    group: apps
    kind: Deployment
    name: app.*  #regexp
    version: v1