package libpod import ( "context" "path/filepath" "strings" "github.com/containers/storage" "github.com/docker/docker/pkg/stringid" "github.com/pkg/errors" "github.com/sirupsen/logrus" ) // Pod represents a group of containers that may share namespaces // ffjson: skip type Pod struct { config *PodConfig state *podState valid bool runtime *Runtime lock storage.Locker } // PodConfig represents a pod's static configuration type PodConfig struct { ID string `json:"id"` Name string `json:"name"` // Labels contains labels applied to the pod Labels map[string]string `json:"labels"` // CgroupParent contains the pod's CGroup parent CgroupParent string `json:"cgroupParent"` // UsePodCgroup indicates whether the pod will create its own CGroup and // join containers to it. // If true, all containers joined to the pod will use the pod cgroup as // their cgroup parent, and cannot set a different cgroup parent UsePodCgroup bool } // podState represents a pod's state type podState struct { // CgroupPath is the path to the pod's CGroup CgroupPath string } // ID retrieves the pod's ID func (p *Pod) ID() string { return p.config.ID } // Name retrieves the pod's name func (p *Pod) Name() string { return p.config.Name } // Labels returns the pod's labels func (p *Pod) Labels() map[string]string { labels := make(map[string]string) for key, value := range p.config.Labels { labels[key] = value } return labels } // CgroupParent returns the pod's CGroup parent func (p *Pod) CgroupParent() string { return p.config.CgroupParent } // UsePodCgroup returns whether containers in the pod will default to this pod's // cgroup instead of the default libpod parent func (p *Pod) UsePodCgroup() bool { return p.config.UsePodCgroup } // CgroupPath returns the path to the pod's CGroup func (p *Pod) CgroupPath() (string, error) { p.lock.Lock() p.lock.Unlock() if err := p.updatePod(); err != nil { return "", err } return p.state.CgroupPath, nil } // Creates a new, empty pod func newPod(lockDir string, runtime *Runtime) (*Pod, error) { pod := new(Pod) pod.config = new(PodConfig) pod.config.ID = stringid.GenerateNonCryptoID() pod.config.Labels = make(map[string]string) pod.state = new(podState) pod.runtime = runtime // Path our lock file will reside at lockPath := filepath.Join(lockDir, pod.config.ID) // Grab a lockfile at the given path lock, err := storage.GetLockfile(lockPath) if err != nil { return nil, errors.Wrapf(err, "error creating lockfile for new pod") } pod.lock = lock return pod, nil } // Update pod state from database func (p *Pod) updatePod() error { if err := p.runtime.state.UpdatePod(p); err != nil { return err } return nil } // Save pod state to database func (p *Pod) save() error { if err := p.runtime.state.SavePod(p); err != nil { return errors.Wrapf(err, "error saving pod %s state") } return nil } // Refresh a pod's state after restart func (p *Pod) refresh() error { p.lock.Lock() defer p.lock.Unlock() if !p.valid { return ErrPodRemoved } // We need to recreate the pod's cgroup if p.config.UsePodCgroup { switch p.runtime.config.CgroupManager { case SystemdCgroupsManager: // NOOP for now, until proper systemd cgroup management // is implemented case CgroupfsCgroupsManager: p.state.CgroupPath = filepath.Join(p.config.CgroupParent, p.ID()) logrus.Debugf("setting pod cgroup to %s", p.state.CgroupPath) default: return errors.Wrapf(ErrInvalidArg, "unknown cgroups manager %s specified", p.runtime.config.CgroupManager) } } // Save changes return p.save() } // Start starts all containers within a pod // It combines the effects of Init() and Start() on a container // If a container has already been initialized it will be started, // otherwise it will be initialized then started. // Containers that are already running or have been paused are ignored // All containers are started independently, in order dictated by their // dependencies. // An error and a map[string]error are returned // If the error is not nil and the map is nil, an error was encountered before // any containers were started // If map is not nil, an error was encountered when starting one or more // containers. The container ID is mapped to the error encountered. The error is // set to ErrCtrExists // If both error and the map are nil, all containers were started successfully func (p *Pod) Start(ctx context.Context) (map[string]error, error) { p.lock.Lock() defer p.lock.Unlock() if !p.valid { return nil, ErrPodRemoved } allCtrs, err := p.runtime.state.PodContainers(p) if err != nil { return nil, err } // Build a dependency graph of containers in the pod graph, err := buildContainerGraph(allCtrs) if err != nil { return nil, errors.Wrapf(err, "error generating dependency graph for pod %s", p.ID()) } ctrErrors := make(map[string]error) ctrsVisited := make(map[string]bool) // If there are no containers without dependencies, we can't start // Error out if len(graph.noDepNodes) == 0 { return nil, errors.Wrapf(ErrNoSuchCtr, "no containers in pod %s have no dependencies, cannot start pod", p.ID()) } // Traverse the graph beginning at nodes with no dependencies for _, node := range graph.noDepNodes { startNode(ctx, node, false, ctrErrors, ctrsVisited) } return ctrErrors, nil } // Visit a node on a container graph and start the container, or set an error if // a dependency failed to start func startNode(ctx context.Context, node *containerNode, setError bool, ctrErrors map[string]error, ctrsVisited map[string]bool) { // First, check if we have already visited the node if ctrsVisited[node.id] { return } // If setError is true, a dependency of us failed // Mark us as failed and recurse if setError { // Mark us as visited, and set an error ctrsVisited[node.id] = true ctrErrors[node.id] = errors.Wrapf(ErrCtrStateInvalid, "a dependency of container %s failed to start", node.id) // Hit anyone who depends on us, and set errors on them too for _, successor := range node.dependedOn { startNode(ctx, successor, true, ctrErrors, ctrsVisited) } return } // Have all our dependencies started? // If not, don't visit the node yet depsVisited := true for _, dep := range node.dependsOn { depsVisited = depsVisited && ctrsVisited[dep.id] } if !depsVisited { // Don't visit us yet, all dependencies are not up // We'll hit the dependencies eventually, and when we do it will // recurse here return } // Going to try to start the container, mark us as visited ctrsVisited[node.id] = true ctrErrored := false // Check if dependencies are running // Graph traversal means we should have started them // But they could have died before we got here // Does not require that the container be locked, we only need to lock // the dependencies depsStopped, err := node.container.checkDependenciesRunning() if err != nil { ctrErrors[node.id] = err ctrErrored = true } else if len(depsStopped) > 0 { // Our dependencies are not running depsList := strings.Join(depsStopped, ",") ctrErrors[node.id] = errors.Wrapf(ErrCtrStateInvalid, "the following dependencies of container %s are not running: %s", node.id, depsList) ctrErrored = true } // Lock before we start node.container.lock.Lock() // Sync the container to pick up current state if !ctrErrored { if err := node.container.syncContainer(); err != nil { ctrErrored = true ctrErrors[node.id] = err } } // Start the container (only if it is not running) if !ctrErrored && node.container.state.State != ContainerStateRunning { if err := node.container.initAndStart(ctx); err != nil { ctrErrored = true ctrErrors[node.id] = err } } node.container.lock.Unlock() // Recurse to anyone who depends on us and start them for _, successor := range node.dependedOn { startNode(ctx, successor, ctrErrored, ctrErrors, ctrsVisited) } return } // Stop stops all containers within a pod that are not already stopped // Each container will use its own stop timeout // Only running containers will be stopped. Paused, stopped, or created // containers will be ignored. // If cleanup is true, mounts and network namespaces will be cleaned up after // the container is stopped. // All containers are stopped independently. An error stopping one container // will not prevent other containers being stopped. // An error and a map[string]error are returned // If the error is not nil and the map is nil, an error was encountered before // any containers were stopped // If map is not nil, an error was encountered when stopping one or more // containers. The container ID is mapped to the error encountered. The error is // set to ErrCtrExists // If both error and the map are nil, all containers were stopped without error func (p *Pod) Stop(cleanup bool) (map[string]error, error) { p.lock.Lock() defer p.lock.Unlock() if !p.valid { return nil, ErrPodRemoved } allCtrs, err := p.runtime.state.PodContainers(p) if err != nil { return nil, err } ctrErrors := make(map[string]error) // TODO: There may be cases where it makes sense to order stops based on // dependencies. Should we bother with this? // Stop to all containers for _, ctr := range allCtrs { ctr.lock.Lock() if err := ctr.syncContainer(); err != nil { ctr.lock.Unlock() ctrErrors[ctr.ID()] = err continue } // Ignore containers that are not running if ctr.state.State != ContainerStateRunning { ctr.lock.Unlock() continue } if err := ctr.stop(ctr.config.StopTimeout); err != nil { ctr.lock.Unlock() ctrErrors[ctr.ID()] = err continue } if cleanup { if err := ctr.cleanup(); err != nil { ctrErrors[ctr.ID()] = err } } ctr.lock.Unlock() } if len(ctrErrors) > 0 { return ctrErrors, errors.Wrapf(ErrCtrExists, "error stopping some containers") } return nil, nil } // Kill sends a signal to all running containers within a pod // Signals will only be sent to running containers. Containers that are not // running will be ignored. All signals are sent independently, and sending will // continue even if some containers encounter errors. // An error and a map[string]error are returned // If the error is not nil and the map is nil, an error was encountered before // any containers were signalled // If map is not nil, an error was encountered when signalling one or more // containers. The container ID is mapped to the error encountered. The error is // set to ErrCtrExists // If both error and the map are nil, all containers were signalled successfully func (p *Pod) Kill(signal uint) (map[string]error, error) { p.lock.Lock() defer p.lock.Unlock() if !p.valid { return nil, ErrPodRemoved } allCtrs, err := p.runtime.state.PodContainers(p) if err != nil { return nil, err } ctrErrors := make(map[string]error) // Send a signal to all containers for _, ctr := range allCtrs { ctr.lock.Lock() if err := ctr.syncContainer(); err != nil { ctr.lock.Unlock() ctrErrors[ctr.ID()] = err continue } // Ignore containers that are not running if ctr.state.State != ContainerStateRunning { ctr.lock.Unlock() continue } if err := ctr.runtime.ociRuntime.killContainer(ctr, signal); err != nil { ctr.lock.Unlock() ctrErrors[ctr.ID()] = err continue } logrus.Debugf("Killed container %s with signal %d", ctr.ID(), signal) } if len(ctrErrors) > 0 { return ctrErrors, nil } return nil, nil } // HasContainer checks if a container is present in the pod func (p *Pod) HasContainer(id string) (bool, error) { if !p.valid { return false, ErrPodRemoved } return p.runtime.state.PodHasContainer(p, id) } // AllContainersByID returns the container IDs of all the containers in the pod func (p *Pod) AllContainersByID() ([]string, error) { p.lock.Lock() defer p.lock.Unlock() if !p.valid { return nil, ErrPodRemoved } return p.runtime.state.PodContainersByID(p) } // AllContainers retrieves the containers in the pod func (p *Pod) AllContainers() ([]*Container, error) { p.lock.Lock() defer p.lock.Unlock() if !p.valid { return nil, ErrPodRemoved } return p.runtime.state.PodContainers(p) } // Status gets the status of all containers in the pod // Returns a map of Container ID to Container Status func (p *Pod) Status() (map[string]ContainerStatus, error) { p.lock.Lock() defer p.lock.Unlock() if !p.valid { return nil, ErrPodRemoved } allCtrs, err := p.runtime.state.PodContainers(p) if err != nil { return nil, err } // We need to lock all the containers for _, ctr := range allCtrs { ctr.lock.Lock() defer ctr.lock.Unlock() } // Now that all containers are locked, get their status status := make(map[string]ContainerStatus, len(allCtrs)) for _, ctr := range allCtrs { if err := ctr.syncContainer(); err != nil { return nil, err } status[ctr.ID()] = ctr.state.State } return status, nil } // TODO add pod batching // Lock pod to avoid lock contention // Store and lock all containers (no RemoveContainer in batch guarantees cache will not become stale)