Manatua. fa'aliliu.: o le tusitala o le tusiga - Erkan Erol, o se inisinia mai le SAP - faʻasoa lana suʻesuʻega i le faiga o le gaioiga a le 'au. kubectl exec, e masani ai tagata uma e galulue ma Kubernetes. Na te faʻatasi ma le algorithm atoa ma lisi o le Kubernetes source code (ma galuega faʻatatau), lea e mafai ai ona e malamalama i le autu i le loloto pe a manaʻomia.
I se tasi Aso Faraile, na sau ai se paaga ia te aʻu ma fesili mai pe faʻapefea ona faʻatino se faʻatonuga i totonu o se pod e faʻaaoga . Sa le mafai ona ou tali atu ia te ia ma faafuasei ona ou iloaina e leai se mea ou te iloa e uiga i le faiga o le galuega kubectl exec. Ioe, sa i ai ni ou manatu patino e uiga i lana masini, ae ou te le 100% mautinoa o latou saʻo ma o lea na ou filifili ai e foia lenei mataupu. I le suʻesuʻeina o blogs, faʻamaumauga ma faʻamatalaga puna, na ou aʻoaʻoina ai le tele, ma i lenei tusiga ou te manaʻo e faʻasoa aʻu mea na maua ma malamalama. Afai ei ai se mea o faaletonu, fa'amolemole fa'afeso'ota'i a'u ile .
Sauniuniga
Ina ia fatuina se fuifui i luga o se MacBook, na ou faʻapipiʻiina . Ona ou faʻasaʻoina lea o tuatusi IP o nodes i le kubeletʻa config, talu ai e le faʻatagaina tulaga faʻaletonu. kubectl exec. E mafai ona e faitau atili e uiga i le mafuaaga autu mo lenei .
- Soʻo se masini = laʻu MacBook
- matai node IP = 192.168.205.10
- Node tagata faigaluega IP = 192.168.205.11
- API server port = 6443
Vaega
- kubectl exec faagasologa: pe a tatou faia "kubectl exec..." ua amata le faagasologa. E mafai ona e faia lenei mea i soʻo se masini e iai le avanoa ile K8s API server. Manatua. transl.: E le gata i lea i le lisi faʻamafanafanaga, o loʻo faʻaogaina e le tusitala le faʻamatalaga "soʻo se masini", o loʻo faʻaalia ai o tulafono nei e mafai ona faʻatinoina i soʻo se masini e mafai ona maua i Kubernetes.
- : O se vaega i le matai pona e maua ai le avanoa i le Kubernetes API. O le pito pito i luma lea mo le vaalele pulea i Kubernetes.
- : sooupu e tamo'e i node uma i le fuifui. E maua ai le galuega o koneteina i totonu o le pod.
- (container runtime): Le polokalame e nafa ma le fa'againa o koneteina. Faataitaiga: Docker, CRI-O, containerd…
- fatu: OS kernel i luga o le node tagata faigaluega; e nafa ma le pulega o faiga.
- taulaʻi (taulai) Fagu: o se atigipusa o se vaega o se pusa ma e tafe i luga o se tasi o pona faigaluega.
O le a le mea na ou mauaina
1. Gaoioiga ile itu ole kalani
Fausia se pusa i totonu o se igoa avanoa default:
// any machine
$ kubectl run exec-test-nginx --image=nginxOna matou faia lea o le exec command ma faʻatali 5000 sekone mo nisi faʻamatalaga:
// any machine
$ kubectl exec -it exec-test-nginx-6558988d5-fgxgg -- sh
# sleep 5000O le kubectl process e aliali mai (faʻatasi ai ma pid = 8507 i la matou mataupu):
// any machine
$ ps -ef |grep kubectl
501 8507 8409 0 7:19PM ttys000 0:00.13 kubectl exec -it exec-test-nginx-6558988d5-fgxgg -- shAfai matou te siakiina le gaioiga o fesoʻotaʻiga o le faagasologa, matou te iloa o loʻo i ai fesoʻotaʻiga i le 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 0x00000028Sei o tatou tilotilo i le code. Kubectl faia se POST talosaga ma se exec subresource ma auina atu se talosaga 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. Gaoioiga i le itu o le matai pona
E mafai foi ona tatou matauina le talosaga ile itu 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]]Manatua o le talosaga HTTP o loʻo aofia ai se talosaga mo suiga o tulafono. fa'atagaina "vaita'i" eseese o stdin/stdout/stderr/spdy-error e fa'atele i luga o se feso'ota'iga TCP e tasi.
E maua e le API server le talosaga ma liliu i 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
}()
Ina ia faia gaioiga manaʻomia, e manaʻomia e le api-server ona iloa poʻo fea pod e manaʻomia ona faʻafesoʻotaʻi:
// 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")
}()
Ioe, o faʻamatalaga e uiga i le pito iʻuga e maua mai faʻamatalaga e uiga i le 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)()
Talofa! Ua iai nei le uafu a Kubelet (node.Status.DaemonEndpoints.KubeletEndpoint.Port) lea e mafai ona fa'afeso'ota'i ai le server API:
// 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
}()
Mai fa'amaumauga :
O nei feso'ota'iga e fa'amutaina i le kubelet's HTTPS endpoint. Ona o le faaletonu, e le faʻamaonia e le apiserver le tusi faamaonia a le kubelet, lea e faʻafefe ai le fesoʻotaʻiga i " osofaʻiga a le tagata-i-le-middle" (MITM) ma le saogalemu e galue i feso'ota'iga le talitonuina ma/po'o le lautele.
O lea ua iloa e le server API le pito ma faʻavaeina se fesoʻotaʻiga:
// 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
}()
Se'i o tatou va'ai po'o le a le mea e tupu i le matai node.
Muamua, saili le IP o le node galue. I la matou tulaga, o le 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://17.3.3Ona seti lea o le kubelet port (10250 i la matou tulaga):
// any machine
$ kubectl get nodes k8s-node-1 -o jsonpath='{.status.daemonEndpoints.kubeletEndpoint}'
map[Port:10250]
Ua o'o nei i le taimi e su'e ai le feso'ota'iga. E i ai se feso'ota'iga i le node tagata faigaluega (192.168.205.11)? O lena! Afai e te "fasiotia" le faagasologa exec, o le a mou atu, o lea ou te iloa ai o le fesoʻotaʻiga na faʻatuina e le api-server ona o se taunuuga o le faʻatonuga faʻatonu.
// master node
$ netstat -atn |grep 192.168.205.11
tcp 0 0 192.168.205.10:37870 192.168.205.11:10250 ESTABLISHED
…
O lo'o tatala pea le feso'ota'iga i le va o le kubectl ma le api-server. E le gata i lea, o loʻo i ai se isi fesoʻotaʻiga e fesoʻotaʻi ai le api-server ma le kubelet.
3. Gaoioiga i luga o le node tagata faigaluega
Se'i o tatou fa'afeso'ota'i i le node o le tagata faigaluega ma va'ai po'o le a le mea o lo'o tupu i luga.
Muamua lava, tatou te iloa o le sootaga ia te ia ua faavaeina foi (laina lona lua); 192.168.205.10 o le IP o le matai node:
// 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
Ae faapefea la tatou au sleep? Hurray, o loʻo i ai foi o ia iina!
// 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
…Ae fa'atali, na fa'apefea ona toso e kubelet lenei mea? O le kubelet ei ai se daemon e tatala le avanoa i le API e ala i le taulaga mo talosaga api-server:
// 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
}()
E fa'atatau e Kubelet le fa'ai'uga tali mo talosaga fa'atonu:
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
}()
Aua le fenumiai. E le toe faʻafoʻi mai le iʻuga o le faʻatonuga, ae o le pito mo le fesoʻotaʻiga:
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 fa'atino se fa'aoga RuntimeServiceClient, o se vaega o le Container Runtime Interface (sa matou tusia atili e uiga i ai, mo se faʻataʻitaʻiga, - tusa. fa'aliliu.):
Lisi umi mai 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)
}
()
Na'o le fa'aaogaina o le gRPC e vala'au ai le metotia e ala i le Container Runtime Interface:
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 e nafa ma le faʻatinoga RuntimeServiceServer:
Lisi umi mai 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)
}
()
Afai o lea, e tatau ona tatou vaʻai i se fesoʻotaʻiga i le va o le kubelet ma le taimi faʻaoga pusa, saʻo? Sei o tatou siaki.
Faʻataʻitaʻi lenei poloaiga i luma ma pe a uma le faʻatonuga exec ma vaʻai le eseesega. I loʻu tulaga, o le eseesega o le:
// worker node
$ ss -a -p |grep kubelet
...
u_str ESTAB 0 0 * 157937 * 157387 users:(("kubelet",pid=5714,fd=33))
...Hmmm… Feso'ota'iga socket unix fou i le va o kubelet (pid=5714) ma se mea e le iloa. O le a se mea? E sa'o, o 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))
...E pei ona e manatua, o le faiga lea o le docker daemon (pid=1186) e faʻatinoina la matou poloaiga:
// 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. Gaoioiga i le taimi o le koneteina
Sei o tatou su'esu'e le CRI-O source code e malamalama ai i le mea o lo'o tupu. I Docker, e tutusa le manatu.
O loʻo i ai se 'auʻaunaga e nafa ma le faʻatinoga 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
}()
I le fa'ai'uga o le filifili, e fa'atino e le koneteina taimi fa'atonu le fa'atonuga i le node o le tagata faigaluega:
// 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
}()
Mulimuli ane, o le kernel e faʻatino poloaiga:
Faamanatu
- E mafai foi e le API Server ona amataina se feso'ota'iga i se kubelet.
- O feso'ota'iga nei e fa'aauau pea se'ia o'o i le fa'ai'uga o le sauniga fa'atino felagolagomai:
- i le va o kubectl ma le api-server;
- i le va o le api-server ma le kubectl;
- i le va o le kubelet ma le koneteina taimi ta'avale.
- Kubectl po'o le api-server e le mafai ona ta'avale so'o se mea i nodes a le tagata faigaluega. E mafai ona tamo'e se kubelet, ae e fegalegaleai foi ma le taimi ole koneteina mo nei gaioiga.
Punaoa
- Talanoaga"» i le kubernetes-dev;
- Mataupu "";
- Talanoaga"»i luga ole Server Fault.
PS mai faaliliu
Faitau foi i la matou blog:
- "O le a le mea e tupu i Kubernetes pe a e tamoe kubectl run?" и ;
- «";
- «";
- «".
puna: www.habr.com