Nota. transl.: auctor articuli - Erkan Erol, ingeniarius ab SAP - communicat studium machinarum machinarum machinarum operandi. kubectl execita omnibus operanti Kubernetes. Totum algorithmum comitatur cum schedulis fonte Codicis Kubernetes (et inceptis affinibus), quod te permittit ut rem quam diligentissime postulabat comprehendere.
Una die Veneris collega ad me accessit et rogavit quomodo mandatum uteretur in vasculo client-go. Cui respondere non potui et subito intellexi me nihil scire de machinatione operationis kubectl exec. Imo certas notiones de structura habui, sed non C% de eorum rectitudine certior factus sum, ideoque hanc rem aggredi decrevi. Cum studui diario, documento et codice fonte, multa nova didici, et in hoc articulo inventa et intelligentiam meam communicare cupio. Si quid mali est, pete Twitter.
Training
Botrus in MacBook creare, ego cloned ecomm-integratio-ballerina/kubernetes-botrus. Deinde emendavi inscriptiones IP nodis in kubelet config, cum occasus defectus non permitteret. kubectl exec. Plura de causa principalis huius legere potes hic.
Aliqua car = my MacBook
Magister nodi IP = 192.168.205.10
Node opifex IP = 192.168.205.11
API servo portum = 6443
components
kubectl exec processus: Cum exequimur "kubectl exec..." processus incepit. Hoc fieri potest in quavis machina accessus ad K8s API servo. Nota praeterea in schedulis consolandis auctor commentarium "quaelibet machina" adhibet, si subsequentia mandata exsecutioni mandari possint in quibusvis machinis accessu ad Kubernetes.
API server: Compositio in nodi magistro aditum Kubernetis API praebet. Haec est frons pro plano moderandi in Kubernetes.
cubelet: agens quod currit omni nodo in botro. Operationem vasculi in vasculo efficit.
Petitionem etiam observare possumus in parte api-servatoris;
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]]
Nota petitionem HTTP includere petitionem mutandi protocollum. SPDY sino vos singulas multiplices stdin/stdout/stderr/spdy-erroris "fluminum" per unum nexum TCP.
API server instantiam accipit et in eam vertit 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
}
Ad actiones debitas faciendas, api-servator scire debet quem vasculum attingere oporteat;
// 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")
}
Utique notitia de fine sumitur ex notitia de nodo;
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)
euge! Kubelet nunc portum habet (node.Status.DaemonEndpoints.KubeletEndpoint.Port), cui API servo coniungere potest:
// 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
}
Hae nexus fiunt ad terminum kubeleti HTTPS. Defalta apiservator libellum kubeleti non comprobat, qui nexum homini in medio (MITM) vulnerabilem facit atque oppugnat. tutum ad opus vacillent et / vel publica retiacula.
Nunc API servo terminum cognoscit et nexum constituit;
// 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
}
Primum invenimus IP node laborantis. In nobis est 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
Deinde portum kubelet pone (10250 in nostro casu);
// any machine
$ kubectl get nodes k8s-node-1 -o jsonpath='{.status.daemonEndpoints.kubeletEndpoint}'
map[Port:10250]
Nunc tempus est retiaculum cohibere. Estne nexus nodi laborantis (192.168.205.11)? Est! Si autem processum occidere exec, peribit, sic scio, quod nexum constitutum est ab api-servo consequenter de mandato execti executi.
Sed expecta: quomodo hoc kubelet trahere off? Cubiculum daemonem habet qui aditum ad API per portum praebet petitionibus api-servorum;
// 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 utensilia interface RuntimeServiceClientquae est pars Continentis Runtime Interface plura de eo scripsimus, e.g. hic — proxime. transl.):
Donec varius ex cri-api in 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)
}
Continens Runtime est reus implementation RuntimeServiceServer:
Donec varius ex cri-api in 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)
}