何时重建podsandbox

在主逻辑SyncPod 里会进行判断
调用computePodActions 里面进而调用podSandboxChanged
看函数注释就能看出来何时认为podsandboxchanged，进而重建

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0.No sandbox for pod 
1.Needs to create a new sandbox when readySandboxCount > 1 or the ready sandbox is not the latest one.
2.Needs to create a new sandbox when network namespace changed.
3.Needs to create a new sandbox when the sandbox does not have an IP address.

但是如果pod没有配置shouldRestartOnFailure，那么返回的changes.CreateSandbox = false

CNI分配失败后会怎样

cni插件是放在dockershim里，是cri的一部分？

上面判断需要createsandbox后
就各种调用，可以看kubelet调用图里，最后发一个cri grpc请求，RunSandBox
如果失败，直接返回err，并生成event，记录trace
然后syncpod在syncloop里，会继续重试，但不会干预调度结果, 会一直在这个node上重试

pod status

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// PodPending means the pod has been accepted by the system, but one or more of the containers
// has not been started. This includes time before being bound to a node, as well as time spent
// pulling images onto the host.
PodPending PodPhase = "Pending"
// PodRunning means the pod has been bound to a node and all of the containers have been started.
// At least one container is still running or is in the process of being restarted.
PodRunning PodPhase = "Running"
// PodSucceeded means that all containers in the pod have voluntarily terminated
// with a container exit code of 0, and the system is not going to restart any of these containers.
PodSucceeded PodPhase = "Succeeded"
// PodFailed means that all containers in the pod have terminated, and at least one container has
// terminated in a failure (exited with a non-zero exit code or was stopped by the system).
PodFailed PodPhase = "Failed"
// PodUnknown means that for some reason the state of the pod could not be obtained, typically due
// to an error in communicating with the host of the pod.
PodUnknown PodPhase = "Unknown"

获取pod内某一项

之前的想法是遍历

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kubectl -n xxxx get pods  -o go-template --template='{{range .items}}{{ range $key, $value := .metadata.labels }}{{if eq $key "paas.sogou.com/app"}}{{$value}}{{"\n"}}{{end}}{{end}}{{end}}'

后来发现go template有个关键字叫index

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kubectl -n xxxx get pod pod-name  --template='{{index .metadata.labels "paas.sogou.com/app"}}'

获取全部

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kubectl -n xxxx get pod --template=='{{range .items}}{{index .metadata.labels "paas.sogou.com/app"}}{{"\n"}}{{end}}'

而且还有--sort-by、custom-columns=、--field-selector