coredns pods use wrong format (x86) on ARM64 server

[Zhanglei Mao]

After deploy the charmed kubernetes v1.15 bundle from (https://api.jujucharms.com/charmstore/v5/charmed-kubernetes-209/archive/bundle.yaml)
which us this "charm: cs:~containers/kubernetes-master-700"

The pods status would show below "CrashLoopBackoff" and "exec format error" of log. This was cuased by use x86 docker image instead of arm64 version.

ubuntu@maas3:~$ kubectl get pods -A
NAMESPACE NAME READY STATUS RESTARTS AGE
...
kube-system coredns-75dc589b9b-6ggxx 0/1 CrashLoopBackOff 25 136m
kube-system coredns-75dc589b9b-vmk49 0/1 CrashLoopBackOff 27 136m

1 ubuntu@maas3:~$ kubectl logs pod/coredns-75dc589b9b-6ggxx -n kube-system
standard_init_linux.go:211: exec user process caused "exec format error"
ubuntu@maas3:~$

ubuntu@infra2-vm06:~$ docker image list
REPOSITORY TAG IMAGE ID CREATED SIZE
image-registry.canonical.com:5000/cdk/coredns/coredns 1.5.1 4ee43bd86fe6 2 months ago 40.8MB

[Zhanglei Mao (zhanglei-mao)]

There is already coredns-arm64 docker image from Canonical private registry as:

ubuntu@infra2-vm02:~$ docker image list
REPOSITORY TAG IMAGE ID CREATED SIZE
image-registry.canonical.com:5000/cdk/coredns/coredns-arm64 1.5.1 eccb4755e655 2 months ago 39.1MB

If pod configure was modified to use this arm64 image, the pods would become working.

ubuntu@maas3:~$ kubectl describe pods/coredns-75dc589b9b-mhr2j -n kube-system |grep -i image-registry
    Image: image-registry.canonical.com:5000/cdk/coredns/coredns-arm64:1.5.1
    Image ID: docker-pullable://image-registry.canonical.com:5000/cdk/coredns/coredns-arm64@sha256:ad065eb4f03b7e4108007947f928434f7de3f0ffa0f2ed729198d5f49329c56e
ubuntu@maas3:~$

1 ubuntu@maas3:~$ kubectl get pods -A
NAMESPACE NAME READY STATUS RESTARTS AGE
...
kube-system coredns-75dc589b9b-mhr2j 1/1 Running 874 6d6h
kube-system coredns-75dc589b9b-xwpdq 1/1 Running 873 6d6h
...

[George Kraft (cynerva)]

This was previously fixed for cdk-addons 1.16:
https://github.com/charmed-kubernetes/cdk-addons/pull/130
https://github.com/charmed-kubernetes/cdk-addons/commit/3595a96696e6cfa56215704997a280d2a3534a06

I've backported it to the 1.15 branch:
https://github.com/charmed-kubernetes/cdk-addons/commit/922b5ec1fb5a7875844eed7520424c78597db7af
https://github.com/charmed-kubernetes/cdk-addons/commit/0a02a313db0b71a049e3a9bb692147bcf99a286c

And the 1.14 branch:
https://github.com/charmed-kubernetes/cdk-addons/commit/b092eeaa6a9d0fcd9d9276395ae1fc0e32e5759b
https://github.com/charmed-kubernetes/cdk-addons/commit/819a6b65459ec669cbc50d35e5de77bdbab8b6b7

Fixes will go out the next time cdk-addons is released to 1.14/stable and 1.15/stable.