Add basic crictl info config with sandboxImage

[afbjorklund]

The "verbose" message now looks like:

{
  "status": {
    "conditions": [
      {
        "type": "RuntimeReady",
        "status": true,
        "reason": "",
        "message": ""
      },
      {
        "type": "NetworkReady",
        "status": false,
        "reason": "NetworkPluginNotReady",
        "message": "docker: network plugin is not ready: cni config uninitialized"
      }
    ]
  },
  "config": {
    "sandboxImage": "registry.k8s.io/pause:3.9"
  }
}

The "quiet" message looks like before.

$ sudo crictl -D=false info -o go-template --template "{{.config.sandboxImage}}"
registry.k8s.io/pause:3.9

kubernetes/kubernetes@d12b4d4

---

Issue #178

[afbjorklund]

Fixes the failure seen in the verbose kubeadm log (with a misleading "fatal", wrapped in info)

[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
W0414 14:07:25.920713   21122 images.go:80] could not find officially supported version of etcd for Kubernetes v1.27.0, falling back to the nearest etcd version (3.5.7-0)
I0414 14:07:25.920739   21122 checks.go:828] using image pull policy: IfNotPresent
I0414 14:07:25.956663   21122 checks.go:846] image exists: registry.k8s.io/kube-apiserver:v1.27.0
I0414 14:07:25.992594   21122 checks.go:846] image exists: registry.k8s.io/kube-controller-manager:v1.27.0
I0414 14:07:26.025759   21122 checks.go:846] image exists: registry.k8s.io/kube-scheduler:v1.27.0
I0414 14:07:26.067020   21122 checks.go:846] image exists: registry.k8s.io/kube-proxy:v1.27.0
I0414 14:07:26.105940   21122 checks.go:833] failed to detect the sandbox image for local container runtime, output: time="2023-04-14T14:07:26Z" level=fatal msg="getting status of runtime: failed to template data: template: tmplExecuteRawJSON:1:9: executing \"tmplExecuteRawJSON\" at <.config.sandboxImage>: map has no entry for key \"config\""
, error: exit status 1
I0414 14:07:26.140339   21122 checks.go:846] image exists: registry.k8s.io/pause:3.9
I0414 14:07:26.178211   21122 checks.go:846] image exists: registry.k8s.io/etcd:3.5.7-0
I0414 14:07:26.213178   21122 checks.go:846] image exists: registry.k8s.io/coredns/coredns:v1.10.1

The new warn line in the log is instead, if forgetting to configure --pod-infra-container-image:

W0414 14:20:45.738047   41856 checks.go:835] detected that the sandbox image "registry.k8s.io/pause:3.6" of the container runtime is inconsistent with that used by kubeadm. It is recommended that using "registry.k8s.io/pause:3.9" as the CRI sandbox image.

[afbjorklund]

There is some cryptic information on what needs to be done, in the kubernetes documentation (linked from kubeadm):

https://kubernetes.io/docs/setup/production-environment/container-runtimes/#override-pause-image-cri-dockerd-mcr

But only for MCR, the "instructions" (hint) are missing for Docker.

$ kubeadm config images list 2>/dev/null | grep pause
registry.k8s.io/pause:3.9

/etc/systemd/system/cri-docker.service.d/10-pause-image.conf

[Service]
ExecStart=
ExecStart=/usr/bin/cri-dockerd --container-runtime-endpoint fd:// --pod-infra-container-image=registry.k8s.io/pause:3.9