Nodyn. traws.: awdur yr erthygl - Erkan Erol, peiriannydd o SAP - yn rhannu ei astudiaeth o fecanweithiau gweithredu tîm kubectl exec, mor gyfarwydd i bawb sy'n gweithio gyda Kubernetes. Mae'n cyd-fynd â'r algorithm cyfan gyda rhestrau o god ffynhonnell Kubernetes (a phrosiectau cysylltiedig), sy'n eich galluogi i ddeall y pwnc mor ddwfn ag sy'n ofynnol.
Un dydd Gwener, daeth cydweithiwr ataf a gofyn sut i weithredu gorchymyn mewn pod gan ddefnyddio . Ni allwn ei ateb a sylweddolais yn sydyn nad oeddwn yn gwybod dim am y mecanwaith gweithredu kubectl exec. Oedd, roedd gennyf rai syniadau am ei strwythur, ond nid oeddwn 100% yn siŵr o’u cywirdeb ac felly penderfynais fynd i’r afael â’r mater hwn. Ar ôl astudio blogiau, dogfennaeth a chod ffynhonnell, dysgais lawer o bethau newydd, ac yn yr erthygl hon rwyf am rannu fy narganfyddiadau a dealltwriaeth. Os oes unrhyw beth o'i le, cysylltwch â mi yn .
Hyfforddiant
I greu clwstwr ar MacBook, nes i glonio . Yna cywirais gyfeiriadau IP y nodau yn y ffurfwedd kubelet, gan nad oedd y gosodiadau diofyn yn caniatáu kubectl exec. Gallwch ddarllen mwy am y prif reswm dros hyn .
- Unrhyw gar = fy MacBook
- Prif nod IP = 192.168.205.10
- Nod y gweithiwr IP = 192.168.205.11
- Porth gweinydd API = 6443
Cydrannau
- proses kubectl exec: Pan fyddwn yn gweithredu “kubectl exec...” mae'r broses yn cychwyn. Gellir gwneud hyn ar unrhyw beiriant sydd â mynediad at weinydd API K8s. Nodyn transl .: Ymhellach yn y rhestrau consol, mae'r awdur yn defnyddio'r sylw “unrhyw beiriant”, gan awgrymu y gellir gweithredu gorchmynion dilynol ar unrhyw beiriannau o'r fath sydd â mynediad i Kubernetes.
- : Cydran ar y prif nod sy'n darparu mynediad i'r Kubernetes API. Dyma flaen yr awyren reoli yn Kubernetes.
- : Asiant sy'n rhedeg ar bob nod yn y clwstwr. Mae'n sicrhau gweithrediad cynwysyddion yn y pod.
- (amser rhedeg cynhwysydd): Y meddalwedd sy'n gyfrifol am redeg cynwysyddion. Enghreifftiau: Dociwr, CRI-O, mewn cynhwysydd…
- cnewyllyn: OS cnewyllyn ar y nod gweithiwr; yn gyfrifol am reoli prosesau.
- targed (targed) cynhwysydd: cynhwysydd sy'n rhan o god ac yn rhedeg ar un o nodau'r gweithiwr.
Beth wnes i ddarganfod
1. Gweithgaredd ochr y cleient
Creu pod mewn gofod enw default:
// any machine
$ kubectl run exec-test-nginx --image=nginxYna rydym yn gweithredu'r gorchymyn exec ac yn aros 5000 eiliad am arsylwadau pellach:
// any machine
$ kubectl exec -it exec-test-nginx-6558988d5-fgxgg -- sh
# sleep 5000Mae'r broses kubectl yn ymddangos (gyda pid = 8507 yn ein hachos ni):
// any machine
$ ps -ef |grep kubectl
501 8507 8409 0 7:19PM ttys000 0:00.13 kubectl exec -it exec-test-nginx-6558988d5-fgxgg -- shOs byddwn yn gwirio gweithgaredd rhwydwaith y broses, byddwn yn canfod bod ganddo gysylltiadau â'r api-server (192.168.205.10.6443):
// 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 0x00000028Gadewch i ni edrych ar y cod. Mae Kubectl yn creu cais POST gyda'r is-adnodd gweithredol ac yn anfon cais REST:
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. Gweithgaredd ar ochr y prif nod
Gallwn hefyd arsylwi ar y cais ar ochr yr api-server:
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]]Sylwch fod y cais HTTP yn cynnwys cais i newid y protocol. yn eich galluogi i amlblecsu “ffrydiau” stdin/stdout/stderr/error-error unigol dros un cysylltiad TCP.
Mae'r gweinydd API yn derbyn y cais ac yn ei drawsnewid yn 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
}()
I gyflawni'r camau gofynnol, rhaid i'r gweinydd api wybod pa god y mae angen iddo gysylltu â hi:
// 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")
}()
Wrth gwrs, mae data am y pwynt terfyn yn cael ei gymryd o wybodaeth am y nod:
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)()
Hwre! Mae gan y kubelet borthladd nawr (node.Status.DaemonEndpoints.KubeletEndpoint.Port), y gall y gweinydd API gysylltu ag ef:
// 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
}()
O'r ddogfennaeth :
Gwneir y cysylltiadau hyn â diweddbwynt HTTPS y kubelet. Yn ddiofyn, nid yw apiserver yn gwirio tystysgrif y kubelet, sy'n gwneud y cysylltiad yn agored i ymosodiadau dyn-yn-y-canol (MITM) a anniogel am weithio mewn rhwydweithiau annibynadwy a/neu gyhoeddus.
Nawr mae'r gweinydd API yn gwybod y diweddbwynt ac yn sefydlu'r cysylltiad:
// 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
}()
Gadewch i ni weld beth sy'n digwydd ar y prif nod.
Yn gyntaf, rydym yn darganfod IP y nod gweithiwr. Yn ein hachos ni mae'n 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://17.3.3Yna gosodwch y porthladd kubelet (10250 yn ein hachos ni):
// any machine
$ kubectl get nodes k8s-node-1 -o jsonpath='{.status.daemonEndpoints.kubeletEndpoint}'
map[Port:10250]
Nawr mae'n bryd gwirio'r rhwydwaith. A oes cysylltiad â nod y gweithiwr (192.168.205.11)? Mae'n! Os byddwch yn lladd proses exec, bydd yn diflannu, felly gwn fod y cysylltiad wedi'i sefydlu gan yr api-server o ganlyniad i'r gorchymyn exe a weithredwyd.
// master node
$ netstat -atn |grep 192.168.205.11
tcp 0 0 192.168.205.10:37870 192.168.205.11:10250 ESTABLISHED
…
Mae'r cysylltiad rhwng kubectl ac api-server yn dal ar agor. Yn ogystal, mae cysylltiad arall sy'n cysylltu api-server a kubelet.
3. Gweithgaredd ar y nod gweithiwr
Nawr, gadewch i ni gysylltu â nod y gweithiwr a gweld beth sy'n digwydd arno.
Yn gyntaf oll, gwelwn fod y cysylltiad ag ef hefyd wedi'i sefydlu (ail linell); 192.168.205.10 yw IP y prif nod:
// 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
Beth am ein tîm sleep? Hurray, mae hi yno hefyd!
// 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
…Ond arhoswch: sut gwnaeth kubelet dynnu hyn i ffwrdd? Mae gan y kubelet ellyll sy'n darparu mynediad i'r API trwy'r porthladd ar gyfer ceisiadau gweinydd api:
// 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
}()
Mae Kubelet yn cyfrifo'r pwynt terfyn ymateb ar gyfer ceisiadau gweithrediaeth:
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
}()
Peidiwch â drysu. Nid yw'n dychwelyd canlyniad y gorchymyn, ond y pwynt terfyn ar gyfer cyfathrebu:
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:"-"`
}()
Mae Kubelet yn gweithredu'r rhyngwyneb RuntimeServiceClient, sy'n rhan o'r Container Runtime Interface (Ysgrifennon ni fwy amdano, er enghraifft, - tua. cyfieithu.):
Rhestr hir o cri-api yn 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)
}
()
Yn syml, mae'n defnyddio gRPC i alw dull trwy'r Rhyngwyneb Rhedeg Cynhwysydd:
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 sy'n gyfrifol am weithredu RuntimeServiceServer:
Rhestr hir o cri-api yn 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)
}
()
Os felly, dylem weld cysylltiad rhwng y kubelet ac amser rhedeg y cynhwysydd, iawn? Gadewch i ni wirio.
Rhedeg y gorchymyn hwn cyn ac ar ôl y gorchymyn exec ac edrych ar y gwahaniaethau. Yn fy achos i, y gwahaniaeth yw:
// worker node
$ ss -a -p |grep kubelet
...
u_str ESTAB 0 0 * 157937 * 157387 users:(("kubelet",pid=5714,fd=33))
...Hmmm... Cysylltiad newydd trwy socedi unix rhwng kubelet (pid=5714) a rhywbeth anhysbys. Beth allai fod? Mae hynny'n iawn, mae'n Docker (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))
...Fel y cofiwch, dyma'r broses daemon docwr (pid = 1186) sy'n gweithredu ein gorchymyn:
// 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. Gweithgaredd yn yr amser rhedeg cynhwysydd
Gadewch i ni archwilio cod ffynhonnell CRI-O i ddeall beth sy'n digwydd. Yn Docker mae'r rhesymeg yn debyg.
Mae gweinydd sy'n gyfrifol am weithredu 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
}()
Ar ddiwedd y gadwyn, mae amser rhedeg y cynhwysydd yn gweithredu'r gorchymyn ar y nod gweithiwr:
// 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
}()
Yn olaf, mae'r cnewyllyn yn gweithredu'r gorchmynion:
Nodiadau atgoffa
- Gall Gweinydd API hefyd gychwyn cysylltiad â'r kubelet.
- Mae'r cysylltiadau canlynol yn parhau hyd nes y daw'r sesiwn gweithredol rhyngweithiol i ben:
- rhwng kubectl ac api-server;
- rhwng api-server a kubectl;
- rhwng y kubelet ac amser rhedeg y cynhwysydd.
- Ni all Kubectl neu api-server redeg unrhyw beth ar nodau gweithwyr. Gall y Kubelet redeg, ond mae hefyd yn rhyngweithio ag amser rhedeg y cynhwysydd i wneud y pethau hynny.
Adnoddau
- Trafodaeth"" yn kubernetes-dev;
- Erthygl "";
- Trafodaeth"" ar Nam Gweinydd.
PS gan y cyfieithydd
Darllenwch hefyd ar ein blog:
- "Beth sy'n digwydd yn Kubernetes pan fyddwch chi'n rhedeg rhedeg kubectl?" и ;
- «";
- «";
- «'.
Ffynhonnell: hab.com