Not. werger.: Nivîskarê gotarê - Erkan Erol, endezyarek ji SAP - lêkolîna xwe ya li ser mekanîzmayên xebata tîmê parve dike kubectl exec, ji bo her kesê ku bi Kubernetes re dixebite ewqas nas e. Ew bi tevahî algorîtmayê re bi navnîşên koda çavkaniyê ya Kubernetes (û projeyên têkildar) re, ku dihêle hûn mijarê bi qasî ku tê xwestin fêm bikin.
Rojek înê, hevkarek hat ba min û jê pirsî ka meriv çawa fermanek di binavê de bi kar tîne . Min nekarî bersîva wî bidim û ji nişkê ve fêhm kir ku ez di derbarê mekanîzmaya xebatê de tiştek nizanim kubectl exec. Erê, min di derheqê strukturê wê de hin ramanên min hebûn, lê ez 100% ji rastbûna wan ne ewle bûm û ji ber vê yekê biryar da ku ez vê pirsgirêkê çareser bikim. Piştî xwendina blogan, belgekirin û koda çavkaniyê, ez fêrî gelek tiştên nû bûm, û di vê gotarê de ez dixwazim vedîtin û têgihîştina xwe parve bikim. Ger tiştek xelet e, ji kerema xwe bi min re têkilî daynin .
Amadekirin
Ji bo ku ez li ser MacBook komeke biafirînim, min klon kir . Dûv re min navnîşanên IP-ya girêkên di mîhenga kubelet de rast kir, ji ber ku mîhengên xwerû destûr nedan kubectl exec. Hûn dikarin li ser sedema sereke ya vê yekê bêtir bixwînin .
- Her otomobîlek = MacBookê min
- Navê sereke IP = 192.168.205.10
- Nodeya karker IP = 192.168.205.11
- Porta servera API = 6443
Components
- pêvajoya kubectl exec: Dema ku em “kubectl exec...” bi darve dikin pêvajo dest pê dike. Ev dikare li ser her makîneyek ku gihîştina servera API ya K8s pêk tê. Not werger.: Wekî din di navnîşên konsolê de, nivîskar şîroveya "her makîneyek" bikar tîne, tê vê wateyê ku emrên paşîn dikarin li ser makîneyên weha yên ku gihîştina Kubernetes-ê têne darve kirin.
- : Parçeyek li ser girêka sereke ku gihîştina Kubernetes API peyda dike. Ev pêşiyê ji bo balafira kontrolê ya li Kubernetes e.
- : Ajanek ku li ser her girêka komê dimeşe. Ew xebata konteynerên di binavê de misoger dike.
- (dema xebitandina konteyner): Nermalava ku ji bo xebitandina konteyneran berpirsiyar e. Nimûne: Docker, CRI-O, konteynir…
- kernel: Kernel OS li ser girêka karker; berpirsiyariya rêveberiya pêvajoyê ye.
- armanc (armanc) têrr: konteynirek ku beşek ji podê ye û li ser yek ji girêkên karker dimeşe.
Tiştê ku min kifş kir
1. Çalakiya aliyê Client
Di nav cîhek navekî de podek çêbikin default:
// any machine
$ kubectl run exec-test-nginx --image=nginxDûv re em fermana exec bicîh dikin û ji bo çavdêriyên din 5000 çirkeyan li bendê ne:
// any machine
$ kubectl exec -it exec-test-nginx-6558988d5-fgxgg -- sh
# sleep 5000Pêvajoya kubectl xuya dike (di doza me de bi pid=8507):
// any machine
$ ps -ef |grep kubectl
501 8507 8409 0 7:19PM ttys000 0:00.13 kubectl exec -it exec-test-nginx-6558988d5-fgxgg -- shGer em çalakiya torê ya pêvajoyê kontrol bikin, em ê bibînin ku pêwendiya wê bi api-server (192.168.205.10.6443) re heye:
// any machine
$ netstat -atnv |grep 8507
tcp4 0 0 192.168.205.1.51673 192.168.205.10.6443 ESTABLISHED 131072 131768 8507 0 0x0102 0x00000020
tcp4 0 0 192.168.205.1.51672 192.168.205.10.6443 ESTABLISHED 131072 131768 8507 0 0x0102 0x00000028Ka em li kodê binêrin. Kubectl bi jêrçavkaniya exec re daxwazek POST diafirîne û daxwazek REST dişîne:
req := restClient.Post().
Resource("pods").
Name(pod.Name).
Namespace(pod.Namespace).
SubResource("exec")
req.VersionedParams(&corev1.PodExecOptions{
Container: containerName,
Command: p.Command,
Stdin: p.Stdin,
Stdout: p.Out != nil,
Stderr: p.ErrOut != nil,
TTY: t.Raw,
}, scheme.ParameterCodec)
return p.Executor.Execute("POST", req.URL(), p.Config, p.In, p.Out, p.ErrOut, t.Raw, sizeQueue)()
2. Çalakî li aliyê node master
Em dikarin daxwazê li ser api-server jî bişopînin:
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]]Têbînî ku daxwaza HTTP daxwazek ji bo guhertina protokolê vedigire. destûrê dide te ku hûn stdin/stdout/stderr/spdy-error "streams" li ser yek pêwendiyek TCP-ê piralî bikin.
Pêşkêşkara API daxwazê distîne û vediguherîne 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
}()
Ji bo pêkanîna çalakiyên pêwîst, api-server divê zanibe ku ew bi kîjan podê re pêdivî ye ku têkilî daynin:
// 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")
}()
Bê guman, daneyên di derbarê xala dawî de ji agahdariya li ser nodê têne girtin:
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)()
Hooray! Kubelet nuha portek heye (node.Status.DaemonEndpoints.KubeletEndpoint.Port), ku servera API dikare pê ve girêbide:
// 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
}()
Ji belgeyê :
Van girêdan bi xala dawiya HTTPS ya kubelet re têne çêkirin. Ji hêla xwerû ve, apiserver sertîfîkaya kubelet-ê verast nake, ku pêwendiyê ji êrişên mirov-in-the-middle (MITM) re xeternak dike û ne ewledar ji bo xebatê di torên nebawer û / an giştî de.
Naha servera API xala dawiyê dizane û pêwendiyê saz dike:
// 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
}()
Ka em bibînin ka li ser girêka masterê çi diqewime.
Pêşîn, em IP-ya girêka karkerê fêr dibin. Di doza me de ew 192.168.205.11 e:
// 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://17.3.3Dûv re porta kubelet saz bikin (di doza me de 10250):
// any machine
$ kubectl get nodes k8s-node-1 -o jsonpath='{.status.daemonEndpoints.kubeletEndpoint}'
map[Port:10250]
Niha wextê kontrolkirina torê ye. Têkiliyek bi girêka karker (192.168.205.11) re heye? Ev e! Ger hûn pêvajoyek bikujin exec, ew ê winda bibe, ji ber vê yekê ez dizanim ku pêwendiya ji hêla api-server ve wekî encama fermana exec hatî darvekirin hate saz kirin.
// master node
$ netstat -atn |grep 192.168.205.11
tcp 0 0 192.168.205.10:37870 192.168.205.11:10250 ESTABLISHED
…
Têkiliya di navbera kubectl û api-server de hîn vekirî ye. Wekî din, pêwendiyek din heye ku api-server û kubelet girêdide.
3. Çalakî li ser girêka karker
Naha werin em bi girêka karker ve girêbidin û bibînin ka li ser çi diqewime.
Beriya her tiştî, em dibînin ku girêdana wê jî pêk tê (xeta duyemîn); 192.168.205.10 IP-ya girêka sereke ye:
// worker node
$ netstat -atn |grep 10250
tcp6 0 0 :::10250 :::* LISTEN
tcp6 0 0 192.168.205.11:10250 192.168.205.10:37870 ESTABLISHED
Çi li ser tîma me sleep? Hurray, ew jî li wir e!
// worker node
$ ps -afx
...
31463 ? Sl 0:00 _ docker-containerd-shim 7d974065bbb3107074ce31c51f5ef40aea8dcd535ae11a7b8f2dd180b8ed583a /var/run/docker/libcontainerd/7d974065bbb3107074ce31c51
31478 pts/0 Ss 0:00 _ sh
31485 pts/0 S+ 0:00 _ sleep 5000
…Lê li bendê bin: Kubelet çawa ev yek derxist? Kubelet xwedan daemonek e ku ji bo daxwazên api-server bi riya portê gihîştina API-yê peyda dike:
// 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
}()
Kubelet ji bo daxwazên exec xala dawiya bersivê hesab dike:
func (s *server) GetExec(req *runtimeapi.ExecRequest) (*runtimeapi.ExecResponse, error) {
if err := validateExecRequest(req); err != nil {
return nil, err
}
token, err := s.cache.Insert(req)
if err != nil {
return nil, err
}
return &runtimeapi.ExecResponse{
Url: s.buildURL("exec", token),
}, nil
}()
Ne şaş bibin. Ew ne encama fermanê vedigere, lê xala dawiyê ji bo ragihandinê vedigere:
type ExecResponse struct {
// Fully qualified URL of the exec streaming server.
Url string `protobuf:"bytes,1,opt,name=url,proto3" json:"url,omitempty"`
XXX_NoUnkeyedLiteral struct{} `json:"-"`
XXX_sizecache int32 `json:"-"`
}()
Kubelet pêvekê pêk tîne RuntimeServiceClient, ku beşek ji Navrûya Runtime Container e (me li ser wê bêtir nivîsî, mînakî, - nêzîkî. werger.):
Lîsteya dirêj ji cri-api di kubernetes/kubernetes de
// 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)
}
()
Ew bi tenê gRPC bikar tîne da ku bi navbeynkariya Runtime Container ve rêbazek bang bike:
type runtimeServiceClient struct {
cc *grpc.ClientConn
}()
func (c *runtimeServiceClient) Exec(ctx context.Context, in *ExecRequest, opts ...grpc.CallOption) (*ExecResponse, error) {
out := new(ExecResponse)
err := c.cc.Invoke(ctx, "/runtime.v1alpha2.RuntimeService/Exec", in, out, opts...)
if err != nil {
return nil, err
}
return out, nil
}()
Container Runtime ji bo pêkanîna berpirsiyar e RuntimeServiceServer:
Lîsteya dirêj ji cri-api di kubernetes/kubernetes de
// 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)
}
()
Ger wusa be, divê em têkiliyek di navbera kubelet û dema xebitandina konteynerê de bibînin, rast? Werin em kontrol bikin.
Berî û piştî fermana exec vê fermanê bimeşînin û li cûdahiyan binihêrin. Di rewşa min de cûdahî ev e:
// worker node
$ ss -a -p |grep kubelet
...
u_str ESTAB 0 0 * 157937 * 157387 users:(("kubelet",pid=5714,fd=33))
...Hmmm... Têkiliyek nû bi riya soketên unix di navbera kubelet (pid=5714) û tiştek nenas de. Çi dibe bila bibe? Rast e, ew Docker e (pid=1186)!
// worker node
$ ss -a -p |grep 157387
...
u_str ESTAB 0 0 * 157937 * 157387 users:(("kubelet",pid=5714,fd=33))
u_str ESTAB 0 0 /var/run/docker.sock 157387 * 157937 users:(("dockerd",pid=1186,fd=14))
...Wekî ku tê bîra we, ev pêvajoya docker daemon e (pid=1186) ku emrê me pêk tîne:
// worker node
$ ps -afx
...
1186 ? Ssl 0:55 /usr/bin/dockerd -H fd://
17784 ? Sl 0:00 _ docker-containerd-shim 53a0a08547b2f95986402d7f3b3e78702516244df049ba6c5aa012e81264aa3c /var/run/docker/libcontainerd/53a0a08547b2f95986402d7f3
17801 pts/2 Ss 0:00 _ sh
17827 pts/2 S+ 0:00 _ sleep 5000
...4. Çalakî di dema runtime konteynir
Ka em koda çavkaniyê ya CRI-O vekolînin da ku fêm bikin ka çi diqewime. Di Docker de mantiq wekhev e.
Serverek berpirsiyar ji bo bicîhkirinê heye RuntimeServiceServer:
// Server implements the RuntimeService and ImageService
type Server struct {
config libconfig.Config
seccompProfile *seccomp.Seccomp
stream StreamService
netPlugin ocicni.CNIPlugin
hostportManager hostport.HostPortManager
appArmorProfile string
hostIP string
bindAddress string
*lib.ContainerServer
monitorsChan chan struct{}
defaultIDMappings *idtools.IDMappings
systemContext *types.SystemContext // Never nil
updateLock sync.RWMutex
seccompEnabled bool
appArmorEnabled bool
}()
// Exec prepares a streaming endpoint to execute a command in the container.
func (s *Server) Exec(ctx context.Context, req *pb.ExecRequest) (resp *pb.ExecResponse, err error) {
const operation = "exec"
defer func() {
recordOperation(operation, time.Now())
recordError(operation, err)
}()
resp, err = s.getExec(req)
if err != nil {
return nil, fmt.Errorf("unable to prepare exec endpoint: %v", err)
}
return resp, nil
}()
Di dawiya zincîrê de, dema xebitandina konteynerê fermanê li ser girêka karker pêk tîne:
// ExecContainer prepares a streaming endpoint to execute a command in the container.
func (r *runtimeOCI) ExecContainer(c *Container, cmd []string, stdin io.Reader, stdout, stderr io.WriteCloser, tty bool, resize <-chan remotecommand.TerminalSize) error {
processFile, err := prepareProcessExec(c, cmd, tty)
if err != nil {
return err
}
defer os.RemoveAll(processFile.Name())
args := []string{rootFlag, r.root, "exec"}
args = append(args, "--process", processFile.Name(), c.ID())
execCmd := exec.Command(r.path, args...)
if v, found := os.LookupEnv("XDG_RUNTIME_DIR"); found {
execCmd.Env = append(execCmd.Env, fmt.Sprintf("XDG_RUNTIME_DIR=%s", v))
}
var cmdErr, copyError error
if tty {
cmdErr = ttyCmd(execCmd, stdin, stdout, resize)
} else {
if stdin != nil {
// Use an os.Pipe here as it returns true *os.File objects.
// This way, if you run 'kubectl exec <pod> -i bash' (no tty) and type 'exit',
// the call below to execCmd.Run() can unblock because its Stdin is the read half
// of the pipe.
r, w, err := os.Pipe()
if err != nil {
return err
}
go func() { _, copyError = pools.Copy(w, stdin) }()
execCmd.Stdin = r
}
if stdout != nil {
execCmd.Stdout = stdout
}
if stderr != nil {
execCmd.Stderr = stderr
}
cmdErr = execCmd.Run()
}
if copyError != nil {
return copyError
}
if exitErr, ok := cmdErr.(*exec.ExitError); ok {
return &utilexec.ExitErrorWrapper{ExitError: exitErr}
}
return cmdErr
}()
Di dawiyê de, kernel fermanan pêk tîne:
Navdêr
- Pêşkêşkara API jî dikare pêwendiyek bi kubelet re dest pê bike.
- Têkiliyên jêrîn heya ku rûniştina exec ya înteraktîf biqede berdewam dikin:
- di navbera kubectl û api-server de;
- di navbera api-server û kubectl de;
- di navbera kubelet û runtime konteynir.
- Kubectl an api-server nikare tiştek li ser girêkên karker bimeşîne. Kubelet dikare bimeşîne, lê ew di heman demê de bi dema xebitandina konteynerê re jî têkilî da ku van tiştan bike.
Çavkaniyên
- Nîqaş"" di kubernetes-dev;
- Gotar "»;
- Nîqaş""li ser xeletiya serverê.
PS ji wergêr
Li ser bloga me jî bixwînin:
- "Gava ku hûn kubectl run dimeşînin di Kubernetes de çi diqewime?" и ;
- «»;
- «»;
- «".
Source: www.habr.com