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cli: Add options for Raft snapshotting

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Add the following options to "swarm init" and "swarm update":

- --max-snapshots: Retain this many old Raft snapshots in addition
  to the latest one

- --snapshot-interval: Number of log entries between Raft snapshots

These options already existed in SwarmKit and the Docker API but were
never exposed in the CLI. I'm adding them here to fix this oversight.

--max-snapshots may be useful for debugging purposes and more
conservative users who want to store rolling backups of old versions of
the Raft state.

--snapshot-interval is most useful for performance tuning. The default
value of 10000 may not be ideal for some setups.

There is also a LogEntriesForSlowFollowers option that is not exposed. I
decided not to expose it along with these others because I don't think
it's generally useful (and I'm not sure what I would call the CLI flag).
But if people want, I can expose it for the sake of completeness.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
This commit is contained in:
Aaron Lehmann 2016-11-02 12:29:51 -07:00
parent 16ea0806f8
commit 842d11f44c
9 changed files with 57 additions and 45 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
api/types/swarm/swarm.go
View file

@ -60,7 +60,7 @@ type RaftConfig struct {
// KeepOldSnapshots is the number of snapshots to keep beyond the
// current snapshot.
KeepOldSnapshots uint64 `json:",omitempty"`
KeepOldSnapshots *uint64 `json:",omitempty"`
// LogEntriesForSlowFollowers is the number of log entries to keep
// around to sync up slow followers after a snapshot is created.

21
cli/command/swarm/opts.go
View file

@ -24,6 +24,8 @@ const (
flagToken = "token"
flagTaskHistoryLimit = "task-history-limit"
flagExternalCA = "external-ca"
flagMaxSnapshots = "max-snapshots"
flagSnapshotInterval = "snapshot-interval"
)
type swarmOptions struct {
@ -31,6 +33,8 @@ type swarmOptions struct {
dispatcherHeartbeat time.Duration
nodeCertExpiry time.Duration
externalCA ExternalCAOption
maxSnapshots uint64
snapshotInterval uint64
}
// NodeAddrOption is a pflag.Value for listening addresses
@ -167,11 +171,11 @@ func addSwarmFlags(flags *pflag.FlagSet, opts *swarmOptions) {
flags.DurationVar(&opts.dispatcherHeartbeat, flagDispatcherHeartbeat, time.Duration(5*time.Second), "Dispatcher heartbeat period")
flags.DurationVar(&opts.nodeCertExpiry, flagCertExpiry, time.Duration(90*24*time.Hour), "Validity period for node certificates")
flags.Var(&opts.externalCA, flagExternalCA, "Specifications of one or more certificate signing endpoints")
flags.Uint64Var(&opts.maxSnapshots, flagMaxSnapshots, 0, "Number of additional Raft snapshots to retain")
flags.Uint64Var(&opts.snapshotInterval, flagSnapshotInterval, 10000, "Number of log entries between Raft snapshots")
}
func (opts *swarmOptions) ToSpec(flags *pflag.FlagSet) swarm.Spec {
spec := swarm.Spec{}
func (opts *swarmOptions) mergeSwarmSpec(spec *swarm.Spec, flags *pflag.FlagSet) {
if flags.Changed(flagTaskHistoryLimit) {
spec.Orchestration.TaskHistoryRetentionLimit = &opts.taskHistoryLimit
}
@ -184,5 +188,16 @@ func (opts *swarmOptions) ToSpec(flags *pflag.FlagSet) swarm.Spec {
if flags.Changed(flagExternalCA) {
spec.CAConfig.ExternalCAs = opts.externalCA.Value()
}
if flags.Changed(flagMaxSnapshots) {
spec.Raft.KeepOldSnapshots = &opts.maxSnapshots
}
if flags.Changed(flagSnapshotInterval) {
spec.Raft.SnapshotInterval = opts.snapshotInterval
}
}
func (opts *swarmOptions) ToSpec(flags *pflag.FlagSet) swarm.Spec {
var spec swarm.Spec
opts.mergeSwarmSpec(&spec, flags)
return spec
}

33
cli/command/swarm/update.go
View file

@ -39,10 +39,7 @@ func runUpdate(dockerCli *command.DockerCli, flags *pflag.FlagSet, opts swarmOpt
return err
}
err = mergeSwarm(&swarm, flags)
if err != nil {
return err
}
opts.mergeSwarmSpec(&swarm.Spec, flags)
err = client.SwarmUpdate(ctx, swarm.Version, swarm.Spec, updateFlags)
if err != nil {
@ -53,31 +50,3 @@ func runUpdate(dockerCli *command.DockerCli, flags *pflag.FlagSet, opts swarmOpt
return nil
}
func mergeSwarm(swarm *swarm.Swarm, flags *pflag.FlagSet) error {
spec := &swarm.Spec
if flags.Changed(flagTaskHistoryLimit) {
taskHistoryRetentionLimit, _ := flags.GetInt64(flagTaskHistoryLimit)
spec.Orchestration.TaskHistoryRetentionLimit = &taskHistoryRetentionLimit
}
if flags.Changed(flagDispatcherHeartbeat) {
if v, err := flags.GetDuration(flagDispatcherHeartbeat); err == nil {
spec.Dispatcher.HeartbeatPeriod = v
}
}
if flags.Changed(flagCertExpiry) {
if v, err := flags.GetDuration(flagCertExpiry); err == nil {
spec.CAConfig.NodeCertExpiry = v
}
}
if flags.Changed(flagExternalCA) {
value := flags.Lookup(flagExternalCA).Value.(*ExternalCAOption)
spec.CAConfig.ExternalCAs = value.Value()
}
return nil
}

3
cli/command/system/info.go
View file

@ -114,6 +114,9 @@ func prettyPrintInfo(dockerCli *command.DockerCli, info types.Info) error {
fmt.Fprintf(dockerCli.Out(), " Task History Retention Limit: %d\n", taskHistoryRetentionLimit)
fmt.Fprintf(dockerCli.Out(), " Raft:\n")
fmt.Fprintf(dockerCli.Out(), " Snapshot Interval: %d\n", info.Swarm.Cluster.Spec.Raft.SnapshotInterval)
if info.Swarm.Cluster.Spec.Raft.KeepOldSnapshots != nil {
fmt.Fprintf(dockerCli.Out(), " Number of Old Snapshots to Retain: %d\n", *info.Swarm.Cluster.Spec.Raft.KeepOldSnapshots)
}
fmt.Fprintf(dockerCli.Out(), " Heartbeat Tick: %d\n", info.Swarm.Cluster.Spec.Raft.HeartbeatTick)
fmt.Fprintf(dockerCli.Out(), " Election Tick: %d\n", info.Swarm.Cluster.Spec.Raft.ElectionTick)
fmt.Fprintf(dockerCli.Out(), " Dispatcher:\n")

4
contrib/completion/bash/docker
View file

@ -2841,14 +2841,14 @@ _docker_swarm_leave() {
_docker_swarm_update() {
case "$prev" in
--cert-expiry|--dispatcher-heartbeat|--task-history-limit)
--cert-expiry|--dispatcher-heartbeat|--max-snapshots|--snapshot-interval|--task-history-limit)
return
;;
esac
case "$cur" in
-*)
COMPREPLY=( $( compgen -W "--cert-expiry --dispatcher-heartbeat --help --task-history-limit" -- "$cur" ) )
COMPREPLY=( $( compgen -W "--cert-expiry --dispatcher-heartbeat --help --max-snapshots --snapshot-interval --task-history-limit" -- "$cur" ) )
;;
esac
}

8
contrib/completion/zsh/_docker
View file

@ -1630,7 +1630,10 @@ __docker_swarm_subcommand() {
"($help)--advertise-addr[Advertised address]:ip\:port: " \
"($help)*--external-ca=[Specifications of one or more certificate signing endpoints]:endpoint: " \
"($help)--force-new-cluster[Force create a new cluster from current state]" \
"($help)--listen-addr=[Listen address]:ip\:port: " && ret=0
"($help)--listen-addr=[Listen address]:ip\:port: " \
"($help)--max-snapshots[Number of additional Raft snapshots to retain]" \
"($help)--snapshot-interval[Number of log entries between Raft snapshots]" \
"($help)--task-history-limit=[Task history retention limit]:limit: " && ret=0
;;
(join)
_arguments $(__docker_arguments) \
@ -1655,7 +1658,10 @@ __docker_swarm_subcommand() {
_arguments $(__docker_arguments) \
$opts_help \
"($help)--cert-expiry=[Validity period for node certificates]:duration: " \
"($help)*--external-ca=[Specifications of one or more certificate signing endpoints]:endpoint: " \
"($help)--dispatcher-heartbeat=[Dispatcher heartbeat period]:duration: " \
"($help)--max-snapshots[Number of additional Raft snapshots to retain]" \
"($help)--snapshot-interval[Number of log entries between Raft snapshots]" \
"($help)--task-history-limit=[Task history retention limit]:limit: " && ret=0
;;
(help)

6
daemon/cluster/convert/swarm.go
View file

@ -21,7 +21,7 @@ func SwarmFromGRPC(c swarmapi.Cluster) types.Swarm {
},
Raft: types.RaftConfig{
SnapshotInterval: c.Spec.Raft.SnapshotInterval,
KeepOldSnapshots: c.Spec.Raft.KeepOldSnapshots,
KeepOldSnapshots: &c.Spec.Raft.KeepOldSnapshots,
LogEntriesForSlowFollowers: c.Spec.Raft.LogEntriesForSlowFollowers,
HeartbeatTick: int(c.Spec.Raft.HeartbeatTick),
ElectionTick: int(c.Spec.Raft.ElectionTick),
@ -82,8 +82,8 @@ func MergeSwarmSpecToGRPC(s types.Spec, spec swarmapi.ClusterSpec) (swarmapi.Clu
if s.Raft.SnapshotInterval != 0 {
spec.Raft.SnapshotInterval = s.Raft.SnapshotInterval
}
if s.Raft.KeepOldSnapshots != 0 {
spec.Raft.KeepOldSnapshots = s.Raft.KeepOldSnapshots
if s.Raft.KeepOldSnapshots != nil {
spec.Raft.KeepOldSnapshots = *s.Raft.KeepOldSnapshots
}
if s.Raft.LogEntriesForSlowFollowers != 0 {
spec.Raft.LogEntriesForSlowFollowers = s.Raft.LogEntriesForSlowFollowers

23
docs/reference/commandline/swarm_init.md
View file

@ -28,6 +28,8 @@ Options:
--force-new-cluster Force create a new cluster from current state
--help Print usage
--listen-addr value Listen address (format: <ip|interface>[:port])
--max-snapshots int Number of additional Raft snapshots to retain
--snapshot-interval int Number of log entries between Raft snapshots
--task-history-limit int Task history retention limit (default 5)
```
@ -64,7 +66,7 @@ This flag sets the validity period for node certificates.
This flags sets the frequency with which nodes are told to use as a
period to report their health.
### `--external-ca value`
### `--external-ca`
This flag sets up the swarm to use an external CA to issue node certificates. The value takes
the form `protocol=X,url=Y`. The value for `protocol` specifies what protocol should be used
@ -75,7 +77,7 @@ The URL specifies the endpoint where signing requests should be submitted.
This flag forces an existing node that was part of a quorum that was lost to restart as a single node Manager without losing its data.
### `--listen-addr value`
### `--listen-addr`
The node listens for inbound swarm manager traffic on this address. The default is to listen on
0.0.0.0:2377. It is also possible to specify a network interface to listen on that interface's
@ -84,7 +86,7 @@ address; for example `--listen-addr eth0:2377`.
Specifying a port is optional. If the value is a bare IP address or interface
name, the default port 2377 will be used.
### `--advertise-addr value`
### `--advertise-addr`
This flag specifies the address that will be advertised to other members of the
swarm for API access and overlay networking. If unspecified, Docker will check
@ -103,6 +105,21 @@ name, the default port 2377 will be used.
This flag sets up task history retention limit.
### `--max-snapshots`
This flag sets the number of old Raft snapshots to retain in addition to the
current Raft snapshots. By default, no old snapshots are retained. This option
may be used for debugging, or to store old snapshots of the swarm state for
disaster recovery purposes.
### `--snapshot-interval`
This flag specifies how many log entries to allow in between Raft snapshots.
Setting this to a higher number will trigger snapshots less frequently.
Snapshots compact the Raft log and allow for more efficient transfer of the
state to new managers. However, there is a performance cost to taking snapshots
frequently.
## Related information
* [swarm join](swarm_join.md)

2
docs/reference/commandline/swarm_update.md
View file

@ -25,6 +25,8 @@ Options:
--dispatcher-heartbeat duration Dispatcher heartbeat period (default 5s)
--external-ca value Specifications of one or more certificate signing endpoints
--help Print usage
--max-snapshots int Number of additional Raft snapshots to retain
--snapshot-interval int Number of log entries between Raft snapshots
--task-history-limit int Task history retention limit (default 5)
```