bootstrap.go

// Copyright 2012, 2013 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.

package bootstrap

import (
	"fmt"
	"os"
	"path/filepath"

	"github.com/juju/errors"
	"github.com/juju/loggo"
	"github.com/juju/utils"

	"github.com/juju/juju/cloudconfig/instancecfg"
	"github.com/juju/juju/constraints"
	"github.com/juju/juju/environs"
	"github.com/juju/juju/environs/imagemetadata"
	"github.com/juju/juju/environs/simplestreams"
	"github.com/juju/juju/environs/storage"
	"github.com/juju/juju/environs/sync"
	"github.com/juju/juju/environs/tools"
	"github.com/juju/juju/network"
	coretools "github.com/juju/juju/tools"
	"github.com/juju/juju/utils/ssh"
	"github.com/juju/juju/version"
)

const noToolsMessage = `Juju cannot bootstrap because no tools are available for your environment.
You may want to use the 'agent-metadata-url' configuration setting to specify the tools location.
`

var (
	logger = loggo.GetLogger("juju.environs.bootstrap")
)

// BootstrapParams holds the parameters for bootstrapping an environment.
type BootstrapParams struct {
	// Constraints are used to choose the initial instance specification,
	// and will be stored in the new environment's state.
	Constraints constraints.Value

	// Placement, if non-empty, holds an environment-specific placement
	// directive used to choose the initial instance.
	Placement string

	// UploadTools reports whether we should upload the local tools and
	// override the environment's specified agent-version.
	UploadTools bool

	// MetadataDir is an optional path to a local directory containing
	// tools and/or image metadata.
	MetadataDir string

	// AgentVersion, if set, determines the exact tools version that
	// will be used to start the Juju agents.
	AgentVersion *version.Number
}

// Bootstrap bootstraps the given environment. The supplied constraints are
// used to provision the instance, and are also set within the bootstrapped
// environment.
func Bootstrap(ctx environs.BootstrapContext, environ environs.Environ, args BootstrapParams) error {
	cfg := environ.Config()
	network.InitializeFromConfig(cfg)
	if secret := cfg.AdminSecret(); secret == "" {
		return errors.Errorf("environment configuration has no admin-secret")
	}
	if authKeys := ssh.SplitAuthorisedKeys(cfg.AuthorizedKeys()); len(authKeys) == 0 {
		// Apparently this can never happen, so it's not tested. But, one day,
		// Config will act differently (it's pretty crazy that, AFAICT, the
		// authorized-keys are optional config settings... but it's impossible
		// to actually *create* a config without them)... and when it does,
		// we'll be here to catch this problem early.
		return errors.Errorf("environment configuration has no authorized-keys")
	}
	if _, hasCACert := cfg.CACert(); !hasCACert {
		return errors.Errorf("environment configuration has no ca-cert")
	}
	if _, hasCAKey := cfg.CAPrivateKey(); !hasCAKey {
		return errors.Errorf("environment configuration has no ca-private-key")
	}

	// Set default tools metadata source, add image metadata source,
	// then verify constraints. Providers may rely on image metadata
	// for constraint validation.
	var imageMetadata []*imagemetadata.ImageMetadata
	if args.MetadataDir != "" {
		var err error
		imageMetadata, err = setPrivateMetadataSources(environ, args.MetadataDir)
		if err != nil {
			return err
		}
	}
	if err := validateConstraints(environ, args.Constraints); err != nil {
		return err
	}

	_, supportsNetworking := environs.SupportsNetworking(environ)

	ctx.Infof("Bootstrapping environment %q", cfg.Name())
	logger.Debugf("environment %q supports service/machine networks: %v", cfg.Name(), supportsNetworking)
	disableNetworkManagement, _ := cfg.DisableNetworkManagement()
	logger.Debugf("network management by juju enabled: %v", !disableNetworkManagement)
	availableTools, err := findAvailableTools(environ, args.AgentVersion, args.Constraints.Arch, args.UploadTools)
	if errors.IsNotFound(err) {
		return errors.New(noToolsMessage)
	} else if err != nil {
		return err
	}
	if lxcMTU, ok := cfg.LXCDefaultMTU(); ok {
		logger.Debugf("using MTU %v for all created LXC containers' network interfaces", lxcMTU)
	}

	// If we're uploading, we must override agent-version;
	// if we're not uploading, we want to ensure we have an
	// agent-version set anyway, to appease FinishInstanceConfig.
	// In the latter case, setBootstrapTools will later set
	// agent-version to the correct thing.
	agentVersion := version.Current.Number.String()
	if args.AgentVersion != nil {
		agentVersion = args.AgentVersion.String()
	}
	if cfg, err = cfg.Apply(map[string]interface{}{
		"agent-version": agentVersion,
	}); err != nil {
		return err
	}
	if err = environ.SetConfig(cfg); err != nil {
		return err
	}

	ctx.Infof("Starting new instance for initial state server")
	arch, series, finalizer, err := environ.Bootstrap(ctx, environs.BootstrapParams{
		Constraints:    args.Constraints,
		Placement:      args.Placement,
		AvailableTools: availableTools,
	})
	if err != nil {
		return err
	}

	matchingTools, err := availableTools.Match(coretools.Filter{
		Arch:   arch,
		Series: series,
	})
	if err != nil {
		return err
	}
	selectedTools, err := setBootstrapTools(environ, matchingTools)
	if err != nil {
		return err
	}
	if selectedTools.URL == "" {
		if !args.UploadTools {
			logger.Warningf("no prepackaged tools available")
		}
		ctx.Infof("Building tools to upload (%s)", selectedTools.Version)
		builtTools, err := sync.BuildToolsTarball(&selectedTools.Version.Number, cfg.AgentStream())
		if err != nil {
			return errors.Annotate(err, "cannot upload bootstrap tools")
		}
		defer os.RemoveAll(builtTools.Dir)
		filename := filepath.Join(builtTools.Dir, builtTools.StorageName)
		selectedTools.URL = fmt.Sprintf("file://%s", filename)
		selectedTools.Size = builtTools.Size
		selectedTools.SHA256 = builtTools.Sha256Hash
	}

	ctx.Infof("Installing Juju agent on bootstrap instance")
	instanceConfig, err := instancecfg.NewBootstrapInstanceConfig(args.Constraints, series)
	if err != nil {
		return err
	}
	instanceConfig.Tools = selectedTools
	instanceConfig.CustomImageMetadata = imageMetadata
	if err := finalizer(ctx, instanceConfig); err != nil {
		return err
	}
	ctx.Infof("Bootstrap agent installed")
	return nil
}

// setBootstrapTools returns the newest tools from the given tools list,
// and updates the agent-version configuration attribute.
func setBootstrapTools(environ environs.Environ, possibleTools coretools.List) (*coretools.Tools, error) {
	if len(possibleTools) == 0 {
		return nil, fmt.Errorf("no bootstrap tools available")
	}
	var newVersion version.Number
	newVersion, toolsList := possibleTools.Newest()
	logger.Infof("newest version: %s", newVersion)
	cfg := environ.Config()
	if agentVersion, _ := cfg.AgentVersion(); agentVersion != newVersion {
		cfg, err := cfg.Apply(map[string]interface{}{
			"agent-version": newVersion.String(),
		})
		if err == nil {
			err = environ.SetConfig(cfg)
		}
		if err != nil {
			return nil, fmt.Errorf("failed to update environment configuration: %v", err)
		}
	}
	bootstrapVersion := newVersion
	// We should only ever bootstrap the exact same version as the client,
	// or we risk bootstrap incompatibility. We still set agent-version to
	// the newest version, so the agent will immediately upgrade itself.
	if !isCompatibleVersion(newVersion, version.Current.Number) {
		compatibleVersion, compatibleTools := findCompatibleTools(possibleTools, version.Current.Number)
		if len(compatibleTools) == 0 {
			logger.Warningf(
				"failed to find %s tools, will attempt to use %s",
				version.Current.Number, newVersion,
			)
		} else {
			bootstrapVersion, toolsList = compatibleVersion, compatibleTools
		}
	}
	logger.Infof("picked bootstrap tools version: %s", bootstrapVersion)
	return toolsList[0], nil
}

// findCompatibleTools finds tools in the list that have the same major, minor
// and patch level as version.Current.
//
// Build number is not important to match; uploaded tools will have
// incremented build number, and we want to match them.
func findCompatibleTools(possibleTools coretools.List, version version.Number) (version.Number, coretools.List) {
	var compatibleTools coretools.List
	for _, tools := range possibleTools {
		if isCompatibleVersion(tools.Version.Number, version) {
			compatibleTools = append(compatibleTools, tools)
		}
	}
	return compatibleTools.Newest()
}

func isCompatibleVersion(v1, v2 version.Number) bool {
	v1.Build = 0
	v2.Build = 0
	return v1.Compare(v2) == 0
}

// setPrivateMetadataSources sets the default tools metadata source
// for tools syncing, and adds an image metadata source after verifying
// the contents.
func setPrivateMetadataSources(env environs.Environ, metadataDir string) ([]*imagemetadata.ImageMetadata, error) {
	logger.Infof("Setting default tools and image metadata sources: %s", metadataDir)
	tools.DefaultBaseURL = metadataDir

	imageMetadataDir := filepath.Join(metadataDir, storage.BaseImagesPath)
	if _, err := os.Stat(imageMetadataDir); err != nil {
		if !os.IsNotExist(err) {
			return nil, errors.Annotate(err, "cannot access image metadata")
		}
		return nil, nil
	}

	baseURL := fmt.Sprintf("file://%s", filepath.ToSlash(imageMetadataDir))
	datasource := simplestreams.NewURLDataSource("bootstrap metadata", baseURL, utils.NoVerifySSLHostnames)

	// Read the image metadata, as we'll want to upload it to the environment.
	imageConstraint := imagemetadata.NewImageConstraint(simplestreams.LookupParams{})
	existingMetadata, _, err := imagemetadata.Fetch(
		[]simplestreams.DataSource{datasource}, imageConstraint, false)
	if err != nil && !errors.IsNotFound(err) {
		return nil, errors.Annotate(err, "cannot read image metadata")
	}

	// Add an image metadata datasource for constraint validation, etc.
	environs.RegisterImageDataSourceFunc("bootstrap metadata", func(environs.Environ) (simplestreams.DataSource, error) {
		return datasource, nil
	})
	logger.Infof("custom image metadata added to search path")
	return existingMetadata, nil
}

func validateConstraints(env environs.Environ, cons constraints.Value) error {
	validator, err := env.ConstraintsValidator()
	if err != nil {
		return err
	}
	unsupported, err := validator.Validate(cons)
	if len(unsupported) > 0 {
		logger.Warningf("unsupported constraints: %v", unsupported)
	}
	return err
}

// EnsureNotBootstrapped returns nil if the environment is not
// bootstrapped, and an error if it is or if the function was not able
// to tell.
func EnsureNotBootstrapped(env environs.Environ) error {
	_, err := env.StateServerInstances()
	// If there is no error determining state server instaces,
	// then we are bootstrapped.
	switch errors.Cause(err) {
	case nil:
		return environs.ErrAlreadyBootstrapped
	case environs.ErrNoInstances:
		// TODO(axw) 2015-02-03 #1417526
		// We should not be relying on this result,
		// as it is possible for there to be no
		// state servers despite the environment
		// being bootstrapped.
		fallthrough
	case environs.ErrNotBootstrapped:
		return nil
	}
	return err
}