Tuhipoka. whakamaori.: te kaituhi o te tuhinga - Erkan Erol, he miihini mai i SAP - ka tohatoha i tana ako mo nga tikanga o te mahi a te roopu. kubectl exec, tino mohio ki nga tangata katoa e mahi tahi ana me Kubernetes. Ka haere tahi ia i te katoa o te algorithm me nga rarangi ingoa o te waehere puna Kubernetes (me nga kaupapa e pa ana), e taea ai e koe te mohio ki te kaupapa kia rite ki te hiahia.
I tetahi Paraire, ka haere mai tetahi hoa mahi ki a au me te patai me pehea te whakahaere i tetahi whakahau i roto i te pod ma te whakamahi kiritaki-haere. Kaore i taea e au te whakautu ki a ia, ka mohio ohorere ahau kaore au i mohio mo te tikanga o te mahi kubectl exec. Ae, he whakaaro au mo tona hanganga, engari kaore au i te 100% i te tino tika, na reira ka whakatau ahau ki te whakatika i tenei take. I te ako i nga blogs, tuhinga me te waehere puna, he maha nga mea hou i akohia e au, a i roto i tenei tuhinga e hiahia ana ahau ki te whakapuaki i aku kitenga me oku mohiotanga. Ki te he tetahi mea, tena waea mai ki ahau i Twitter.
Whakangungu
Ki te hanga i te tautau ki runga i te MacBook, ka kati ahau ecomm-integration-ballerina/kubernetes-cluster. Na ka whakatikahia e ahau nga wahitau IP o nga pona i roto i te kubelet config, na te mea kaore i whakaaetia e nga tautuhinga taunoa kubectl exec. Ka taea e koe te panui atu mo te take matua mo tenei konei.
Tetahi waka = taku MacBook
IP kōpuku matua = 192.168.205.10
IP kōpuku kaimahi = 192.168.205.11
Tauranga tūmau API = 6443
Tuhinga
tukanga kubectl exec: Ina mahia e matou "kubectl exec..." ka timata te mahi. Ka taea tenei i runga i tetahi miihini me te uru ki te K8s API tūmau. Tuhipoka transl.: I tua atu i nga rarangi papatohu, ka whakamahia e te kaituhi te korero "tetahi mihini", e kii ana ka taea te whakahaere i nga whakahau o muri mai i runga i nga miihini penei me te uru ki a Kubernetes.
tūmau api: He waahanga kei runga i te node matua e tuku urunga ki te API Kubernetes. Koinei te pito o mua mo te waka rererangi whakahaere i Kubernetes.
kubelet: He kaihoko e rere ana i runga i ia node o te tautau. Ka whakarite i te mahi o nga ipu kei roto i te peera.
wā whakahaere ipu (waa whakahaere ipu): Ko te rorohiko te kawenga mo te whakahaere ipu. Tauira: Docker, CRI-O, containerd…
kakano: OS kernel i runga i te node kaimahi; kei a ia te kawenga mo te whakahaere tukanga.
ūnga (whāngai) pouaka: he ipu he wahanga o te pākākano ka rere ki runga i tetahi o nga pona kaimahi.
Ko nga mea i kitea e au
1. Mahi taha kiritaki
Waihangatia he poro i roto i te mokowāingoa default:
// any machine
$ kubectl run exec-test-nginx --image=nginx
Na ka mahia e matou te whakahau exec ka tatari mo te 5000 hēkona mo etahi atu tirohanga:
// any machine
$ kubectl exec -it exec-test-nginx-6558988d5-fgxgg -- sh
# sleep 5000
Ka puta te tukanga kubectl (me te pid=8507 i roto i ta maatau keehi):
Ka taea hoki e matou te kite i te tono i te taha o te api-tūmau:
handler.go:143] kube-apiserver: POST "/api/v1/namespaces/default/pods/exec-test-nginx-6558988d5-fgxgg/exec" satisfied by gorestful with webservice /api/v1
upgradeaware.go:261] Connecting to backend proxy (intercepting redirects) https://192.168.205.11:10250/exec/default/exec-test-nginx-6558988d5-fgxgg/exec-test-nginx?command=sh&input=1&output=1&tty=1
Headers: map[Connection:[Upgrade] Content-Length:[0] Upgrade:[SPDY/3.1] User-Agent:[kubectl/v1.12.10 (darwin/amd64) kubernetes/e3c1340] X-Forwarded-For:[192.168.205.1] X-Stream-Protocol-Version:[v4.channel.k8s.io v3.channel.k8s.io v2.channel.k8s.io channel.k8s.io]]
Kia mahara kei roto i te tono HTTP he tono ki te whakarereke i te kawa. SPDY ka taea e koe te maha o nga stdin / stdout / stderr / spdy-hapa "nga awa" mo te hononga TCP kotahi.
Ka whiwhi te tūmau API i te tono ka huri ki roto PodExecOptions:
// PodExecOptions is the query options to a Pod's remote exec call
type PodExecOptions struct {
metav1.TypeMeta
// Stdin if true indicates that stdin is to be redirected for the exec call
Stdin bool
// Stdout if true indicates that stdout is to be redirected for the exec call
Stdout bool
// Stderr if true indicates that stderr is to be redirected for the exec call
Stderr bool
// TTY if true indicates that a tty will be allocated for the exec call
TTY bool
// Container in which to execute the command.
Container string
// Command is the remote command to execute; argv array; not executed within a shell.
Command []string
}
Hei mahi i nga mahi e hiahiatia ana, me mohio te api-server ko tehea te peera me whakapiri atu:
// ExecLocation returns the exec URL for a pod container. If opts.Container is blank
// and only one container is present in the pod, that container is used.
func ExecLocation(
getter ResourceGetter,
connInfo client.ConnectionInfoGetter,
ctx context.Context,
name string,
opts *api.PodExecOptions,
) (*url.URL, http.RoundTripper, error) {
return streamLocation(getter, connInfo, ctx, name, opts, opts.Container, "exec")
}
Ae ra, ko nga raraunga mo te pito mutunga ka tangohia mai i nga korero mo te node:
nodeName := types.NodeName(pod.Spec.NodeName)
if len(nodeName) == 0 {
// If pod has not been assigned a host, return an empty location
return nil, nil, errors.NewBadRequest(fmt.Sprintf("pod %s does not have a host assigned", name))
}
nodeInfo, err := connInfo.GetConnectionInfo(ctx, nodeName)
Hore! He tauranga kei te kubelet inaianei (node.Status.DaemonEndpoints.KubeletEndpoint.Port), ka taea e te tūmau API te hono atu:
// GetConnectionInfo retrieves connection info from the status of a Node API object.
func (k *NodeConnectionInfoGetter) GetConnectionInfo(ctx context.Context, nodeName types.NodeName) (*ConnectionInfo, error) {
node, err := k.nodes.Get(ctx, string(nodeName), metav1.GetOptions{})
if err != nil {
return nil, err
}
// Find a kubelet-reported address, using preferred address type
host, err := nodeutil.GetPreferredNodeAddress(node, k.preferredAddressTypes)
if err != nil {
return nil, err
}
// Use the kubelet-reported port, if present
port := int(node.Status.DaemonEndpoints.KubeletEndpoint.Port)
if port <= 0 {
port = k.defaultPort
}
return &ConnectionInfo{
Scheme: k.scheme,
Hostname: host,
Port: strconv.Itoa(port),
Transport: k.transport,
}, nil
}
Ka mahia enei hononga ki te pito mutunga HTTPS o te kubelet. Ma te taunoa, kaore te apiserver e manatoko i te tiwhikete o te kubelet, ka whakaraerae te hononga ki nga whakaeke tangata-i-te-waenganui (MITM) me kore haumaru mo te mahi i roto i nga whatunga kore pono me/ranei.
Inaianei kei te mohio te tūmau API ki te pito mutunga ka whakatauhia te hononga:
// Connect returns a handler for the pod exec proxy
func (r *ExecREST) Connect(ctx context.Context, name string, opts runtime.Object, responder rest.Responder) (http.Handler, error) {
execOpts, ok := opts.(*api.PodExecOptions)
if !ok {
return nil, fmt.Errorf("invalid options object: %#v", opts)
}
location, transport, err := pod.ExecLocation(r.Store, r.KubeletConn, ctx, name, execOpts)
if err != nil {
return nil, err
}
return newThrottledUpgradeAwareProxyHandler(location, transport, false, true, true, responder), nil
}
Kia kite tatou he aha te mahi i runga i te node matua.
Tuatahi, ka kitea e matou te IP o te node kaimahi. I roto i ta maatau ko 192.168.205.11:
// any machine
$ kubectl get nodes k8s-node-1 -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
k8s-node-1 Ready <none> 9h v1.15.3 192.168.205.11 <none> Ubuntu 16.04.6 LTS 4.4.0-159-generic docker://17.3.3
Na ka tautuhi i te tauranga kubelet (10250 i roto i ta maatau keehi):
// any machine
$ kubectl get nodes k8s-node-1 -o jsonpath='{.status.daemonEndpoints.kubeletEndpoint}'
map[Port:10250]
Inaianei kua tae ki te wa ki te tirotiro i te whatunga. He hononga ki te node kaimahi (192.168.205.11)? Ko te! Mena ka patu koe i tetahi tukanga exec, ka ngaro, no reira e mohio ana ahau i whakapumautia te hononga e te api-server na te whakahau exec i mahia.
Engari tatari: i pehea te kubelet i tango i tenei? He daemon te kubelet e whakarato ana i te uru ki te API ma te tauranga mo nga tono api-tūmau:
// Server is the library interface to serve the stream requests.
type Server interface {
http.Handler
// Get the serving URL for the requests.
// Requests must not be nil. Responses may be nil iff an error is returned.
GetExec(*runtimeapi.ExecRequest) (*runtimeapi.ExecResponse, error)
GetAttach(req *runtimeapi.AttachRequest) (*runtimeapi.AttachResponse, error)
GetPortForward(*runtimeapi.PortForwardRequest) (*runtimeapi.PortForwardResponse, error)
// Start the server.
// addr is the address to serve on (address:port) stayUp indicates whether the server should
// listen until Stop() is called, or automatically stop after all expected connections are
// closed. Calling Get{Exec,Attach,PortForward} increments the expected connection count.
// Function does not return until the server is stopped.
Start(stayUp bool) error
// Stop the server, and terminate any open connections.
Stop() error
}
Ka whakatinanahia e Kubelet te atanga RuntimeServiceClient, he wahanga o te Atanga Waa Whakahaere Ipu (i tuhia e matou etahi atu korero mo taua mea, hei tauira, konei — āhua. whakawhiti.):
He raarangi roa mai i te cri-api i kubernetes/kubernetes
// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://godoc.org/google.golang.org/grpc#ClientConn.NewStream.
type RuntimeServiceClient interface {
// Version returns the runtime name, runtime version, and runtime API version.
Version(ctx context.Context, in *VersionRequest, opts ...grpc.CallOption) (*VersionResponse, error)
// RunPodSandbox creates and starts a pod-level sandbox. Runtimes must ensure
// the sandbox is in the ready state on success.
RunPodSandbox(ctx context.Context, in *RunPodSandboxRequest, opts ...grpc.CallOption) (*RunPodSandboxResponse, error)
// StopPodSandbox stops any running process that is part of the sandbox and
// reclaims network resources (e.g., IP addresses) allocated to the sandbox.
// If there are any running containers in the sandbox, they must be forcibly
// terminated.
// This call is idempotent, and must not return an error if all relevant
// resources have already been reclaimed. kubelet will call StopPodSandbox
// at least once before calling RemovePodSandbox. It will also attempt to
// reclaim resources eagerly, as soon as a sandbox is not needed. Hence,
// multiple StopPodSandbox calls are expected.
StopPodSandbox(ctx context.Context, in *StopPodSandboxRequest, opts ...grpc.CallOption) (*StopPodSandboxResponse, error)
// RemovePodSandbox removes the sandbox. If there are any running containers
// in the sandbox, they must be forcibly terminated and removed.
// This call is idempotent, and must not return an error if the sandbox has
// already been removed.
RemovePodSandbox(ctx context.Context, in *RemovePodSandboxRequest, opts ...grpc.CallOption) (*RemovePodSandboxResponse, error)
// PodSandboxStatus returns the status of the PodSandbox. If the PodSandbox is not
// present, returns an error.
PodSandboxStatus(ctx context.Context, in *PodSandboxStatusRequest, opts ...grpc.CallOption) (*PodSandboxStatusResponse, error)
// ListPodSandbox returns a list of PodSandboxes.
ListPodSandbox(ctx context.Context, in *ListPodSandboxRequest, opts ...grpc.CallOption) (*ListPodSandboxResponse, error)
// CreateContainer creates a new container in specified PodSandbox
CreateContainer(ctx context.Context, in *CreateContainerRequest, opts ...grpc.CallOption) (*CreateContainerResponse, error)
// StartContainer starts the container.
StartContainer(ctx context.Context, in *StartContainerRequest, opts ...grpc.CallOption) (*StartContainerResponse, error)
// StopContainer stops a running container with a grace period (i.e., timeout).
// This call is idempotent, and must not return an error if the container has
// already been stopped.
// TODO: what must the runtime do after the grace period is reached?
StopContainer(ctx context.Context, in *StopContainerRequest, opts ...grpc.CallOption) (*StopContainerResponse, error)
// RemoveContainer removes the container. If the container is running, the
// container must be forcibly removed.
// This call is idempotent, and must not return an error if the container has
// already been removed.
RemoveContainer(ctx context.Context, in *RemoveContainerRequest, opts ...grpc.CallOption) (*RemoveContainerResponse, error)
// ListContainers lists all containers by filters.
ListContainers(ctx context.Context, in *ListContainersRequest, opts ...grpc.CallOption) (*ListContainersResponse, error)
// ContainerStatus returns status of the container. If the container is not
// present, returns an error.
ContainerStatus(ctx context.Context, in *ContainerStatusRequest, opts ...grpc.CallOption) (*ContainerStatusResponse, error)
// UpdateContainerResources updates ContainerConfig of the container.
UpdateContainerResources(ctx context.Context, in *UpdateContainerResourcesRequest, opts ...grpc.CallOption) (*UpdateContainerResourcesResponse, error)
// ReopenContainerLog asks runtime to reopen the stdout/stderr log file
// for the container. This is often called after the log file has been
// rotated. If the container is not running, container runtime can choose
// to either create a new log file and return nil, or return an error.
// Once it returns error, new container log file MUST NOT be created.
ReopenContainerLog(ctx context.Context, in *ReopenContainerLogRequest, opts ...grpc.CallOption) (*ReopenContainerLogResponse, error)
// ExecSync runs a command in a container synchronously.
ExecSync(ctx context.Context, in *ExecSyncRequest, opts ...grpc.CallOption) (*ExecSyncResponse, error)
// Exec prepares a streaming endpoint to execute a command in the container.
Exec(ctx context.Context, in *ExecRequest, opts ...grpc.CallOption) (*ExecResponse, error)
// Attach prepares a streaming endpoint to attach to a running container.
Attach(ctx context.Context, in *AttachRequest, opts ...grpc.CallOption) (*AttachResponse, error)
// PortForward prepares a streaming endpoint to forward ports from a PodSandbox.
PortForward(ctx context.Context, in *PortForwardRequest, opts ...grpc.CallOption) (*PortForwardResponse, error)
// ContainerStats returns stats of the container. If the container does not
// exist, the call returns an error.
ContainerStats(ctx context.Context, in *ContainerStatsRequest, opts ...grpc.CallOption) (*ContainerStatsResponse, error)
// ListContainerStats returns stats of all running containers.
ListContainerStats(ctx context.Context, in *ListContainerStatsRequest, opts ...grpc.CallOption) (*ListContainerStatsResponse, error)
// UpdateRuntimeConfig updates the runtime configuration based on the given request.
UpdateRuntimeConfig(ctx context.Context, in *UpdateRuntimeConfigRequest, opts ...grpc.CallOption) (*UpdateRuntimeConfigResponse, error)
// Status returns the status of the runtime.
Status(ctx context.Context, in *StatusRequest, opts ...grpc.CallOption) (*StatusResponse, error)
}
Ko te Waa Whakahaere Ipu te kawenga mo te whakatinanatanga RuntimeServiceServer:
He raarangi roa mai i te cri-api i kubernetes/kubernetes
// RuntimeServiceServer is the server API for RuntimeService service.
type RuntimeServiceServer interface {
// Version returns the runtime name, runtime version, and runtime API version.
Version(context.Context, *VersionRequest) (*VersionResponse, error)
// RunPodSandbox creates and starts a pod-level sandbox. Runtimes must ensure
// the sandbox is in the ready state on success.
RunPodSandbox(context.Context, *RunPodSandboxRequest) (*RunPodSandboxResponse, error)
// StopPodSandbox stops any running process that is part of the sandbox and
// reclaims network resources (e.g., IP addresses) allocated to the sandbox.
// If there are any running containers in the sandbox, they must be forcibly
// terminated.
// This call is idempotent, and must not return an error if all relevant
// resources have already been reclaimed. kubelet will call StopPodSandbox
// at least once before calling RemovePodSandbox. It will also attempt to
// reclaim resources eagerly, as soon as a sandbox is not needed. Hence,
// multiple StopPodSandbox calls are expected.
StopPodSandbox(context.Context, *StopPodSandboxRequest) (*StopPodSandboxResponse, error)
// RemovePodSandbox removes the sandbox. If there are any running containers
// in the sandbox, they must be forcibly terminated and removed.
// This call is idempotent, and must not return an error if the sandbox has
// already been removed.
RemovePodSandbox(context.Context, *RemovePodSandboxRequest) (*RemovePodSandboxResponse, error)
// PodSandboxStatus returns the status of the PodSandbox. If the PodSandbox is not
// present, returns an error.
PodSandboxStatus(context.Context, *PodSandboxStatusRequest) (*PodSandboxStatusResponse, error)
// ListPodSandbox returns a list of PodSandboxes.
ListPodSandbox(context.Context, *ListPodSandboxRequest) (*ListPodSandboxResponse, error)
// CreateContainer creates a new container in specified PodSandbox
CreateContainer(context.Context, *CreateContainerRequest) (*CreateContainerResponse, error)
// StartContainer starts the container.
StartContainer(context.Context, *StartContainerRequest) (*StartContainerResponse, error)
// StopContainer stops a running container with a grace period (i.e., timeout).
// This call is idempotent, and must not return an error if the container has
// already been stopped.
// TODO: what must the runtime do after the grace period is reached?
StopContainer(context.Context, *StopContainerRequest) (*StopContainerResponse, error)
// RemoveContainer removes the container. If the container is running, the
// container must be forcibly removed.
// This call is idempotent, and must not return an error if the container has
// already been removed.
RemoveContainer(context.Context, *RemoveContainerRequest) (*RemoveContainerResponse, error)
// ListContainers lists all containers by filters.
ListContainers(context.Context, *ListContainersRequest) (*ListContainersResponse, error)
// ContainerStatus returns status of the container. If the container is not
// present, returns an error.
ContainerStatus(context.Context, *ContainerStatusRequest) (*ContainerStatusResponse, error)
// UpdateContainerResources updates ContainerConfig of the container.
UpdateContainerResources(context.Context, *UpdateContainerResourcesRequest) (*UpdateContainerResourcesResponse, error)
// ReopenContainerLog asks runtime to reopen the stdout/stderr log file
// for the container. This is often called after the log file has been
// rotated. If the container is not running, container runtime can choose
// to either create a new log file and return nil, or return an error.
// Once it returns error, new container log file MUST NOT be created.
ReopenContainerLog(context.Context, *ReopenContainerLogRequest) (*ReopenContainerLogResponse, error)
// ExecSync runs a command in a container synchronously.
ExecSync(context.Context, *ExecSyncRequest) (*ExecSyncResponse, error)
// Exec prepares a streaming endpoint to execute a command in the container.
Exec(context.Context, *ExecRequest) (*ExecResponse, error)
// Attach prepares a streaming endpoint to attach to a running container.
Attach(context.Context, *AttachRequest) (*AttachResponse, error)
// PortForward prepares a streaming endpoint to forward ports from a PodSandbox.
PortForward(context.Context, *PortForwardRequest) (*PortForwardResponse, error)
// ContainerStats returns stats of the container. If the container does not
// exist, the call returns an error.
ContainerStats(context.Context, *ContainerStatsRequest) (*ContainerStatsResponse, error)
// ListContainerStats returns stats of all running containers.
ListContainerStats(context.Context, *ListContainerStatsRequest) (*ListContainerStatsResponse, error)
// UpdateRuntimeConfig updates the runtime configuration based on the given request.
UpdateRuntimeConfig(context.Context, *UpdateRuntimeConfigRequest) (*UpdateRuntimeConfigResponse, error)
// Status returns the status of the runtime.
Status(context.Context, *StatusRequest) (*StatusResponse, error)
}
Ki te pera, me kite tatou i te hononga i waenga i te kubelet me te wa whakahaere ipu, tika? Kia tirohia.
Whakahaerehia tenei whakahau i mua, i muri i te whakahau exec ka titiro ki nga rereketanga. I taku keehi ko te rereke:
// worker node
$ ss -a -p |grep kubelet
...
u_str ESTAB 0 0 * 157937 * 157387 users:(("kubelet",pid=5714,fd=33))
...
Hmmm... He hononga hou ma nga turanga unix i waenga i te kubelet (pid=5714) me tetahi mea e kore e mohiotia. He aha pea? Ka tika, ko Docker (pid=1186)!
Ka taea hoki e te Tūmau API te arawhiti he hononga ki te kubelet.
Ka mau tonu nga hononga e whai ake nei kia mutu ra ano te huihuinga whakahaere tauwhitiwhiti:
i waenganui i te kubectl me te api-tūmau;
i waenganui i te api-tūmau me te kubectl;
i waenganui i te kubelet me te wa whakahaere ipu.
E kore e taea e Kubectl, api-tūmau ranei te whakahaere i tetahi mea ki nga pona kaimahi. Ka taea e te Kubelet te rere, engari ka pahekoheko ki te wa whakahaere ipu hei mahi i aua mahi.