k3s/pkg/cluster/managed.go

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package cluster
// A managed database is one whose lifecycle we control - initializing the cluster, adding/removing members, taking snapshots, etc.
// This is currently just used for the embedded etcd datastore. Kine and other external etcd clusters are NOT considered managed.
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import (
"context"
"fmt"
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"net/http"
"os"
"strings"
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"time"
"github.com/rancher/k3s/pkg/etcd"
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"github.com/rancher/k3s/pkg/cluster/managed"
"github.com/rancher/k3s/pkg/version"
"github.com/rancher/kine/pkg/endpoint"
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"github.com/sirupsen/logrus"
)
// testClusterDB returns a channel that will be closed when the datastore connection is available.
// The datastore is tested for readiness every 5 seconds until the test succeeds.
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func (c *Cluster) testClusterDB(ctx context.Context) (<-chan struct{}, error) {
result := make(chan struct{})
if c.managedDB == nil {
close(result)
return result, nil
}
go func() {
defer close(result)
for {
if err := c.managedDB.Test(ctx); err != nil {
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logrus.Infof("Failed to test data store connection: %v", err)
} else {
logrus.Info(c.managedDB.EndpointName() + " data store connection OK")
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return
}
select {
case <-time.After(5 * time.Second):
case <-ctx.Done():
return
}
}
}()
return result, nil
}
// start starts the database, unless a cluster reset has been requested, in which case
// it does that instead.
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func (c *Cluster) start(ctx context.Context) error {
resetFile := etcd.ResetFile(c.config)
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if c.managedDB == nil {
return nil
}
if c.config.ClusterReset {
if _, err := os.Stat(resetFile); err != nil {
if !os.IsNotExist(err) {
return err
}
} else {
return fmt.Errorf("cluster-reset was successfully performed, please remove the cluster-reset flag and start %s normally, if you need to perform another cluster reset, you must first manually delete the %s file", version.Program, resetFile)
}
return c.managedDB.Reset(ctx)
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}
// removing the reset file and ignore error if the file doesnt exist
os.Remove(resetFile)
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return c.managedDB.Start(ctx, c.clientAccessInfo)
}
// initClusterDB registers routes for database info with the http request handler
func (c *Cluster) initClusterDB(ctx context.Context, handler http.Handler) (http.Handler, error) {
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if c.managedDB == nil {
return handler, nil
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}
if !strings.HasPrefix(c.config.Datastore.Endpoint, c.managedDB.EndpointName()+"://") {
c.config.Datastore = endpoint.Config{
Endpoint: c.managedDB.EndpointName(),
}
}
return c.managedDB.Register(ctx, c.config, handler)
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}
// assignManagedDriver assigns a driver based on a number of different configuration variables.
// If a driver has been initialized it is used.
// If the configured endpoint matches the name of a driver, that driver is used.
// If no specific endpoint has been requested and creating or joining has been requested,
// we use the default driver.
// If none of the above are true, no managed driver is assigned.
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func (c *Cluster) assignManagedDriver(ctx context.Context) error {
// Check all managed drivers for an initialized database on disk; use one if found
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for _, driver := range managed.Registered() {
if ok, err := driver.IsInitialized(ctx, c.config); err != nil {
return err
} else if ok {
c.managedDB = driver
return nil
}
}
// This is needed to allow downstreams to override driver selection logic by
// setting ServerConfig.Datastore.Endpoint such that it will match a driver's EndpointName
endpointType := strings.SplitN(c.config.Datastore.Endpoint, ":", 2)[0]
for _, driver := range managed.Registered() {
if endpointType == driver.EndpointName() {
c.managedDB = driver
return nil
}
}
// If we have been asked to initialize or join a cluster, do so using the default managed database.
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if c.config.Datastore.Endpoint == "" && (c.config.ClusterInit || (c.config.Token != "" && c.config.JoinURL != "")) {
for _, driver := range managed.Registered() {
if driver.EndpointName() == managed.Default() {
c.managedDB = driver
return nil
}
}
}
return nil
}