Add --pids-limit flag to docker update

Signed-off-by: Sunny Gogoi <indiasuny000@gmail.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/command/container/update.go

@@ -27,6 +27,7 @@ type updateOptions struct {
 	memorySwap         opts.MemSwapBytes
 	kernelMemory       opts.MemBytes
 	restartPolicy      string
+	pidsLimit          int64
 	cpus               opts.NanoCPUs
 
 	nFlag int
@@ -65,6 +66,8 @@ func NewUpdateCommand(dockerCli command.Cli) *cobra.Command {
 	flags.Var(&options.memorySwap, "memory-swap", "Swap limit equal to memory plus swap: '-1' to enable unlimited swap")
 	flags.Var(&options.kernelMemory, "kernel-memory", "Kernel memory limit")
 	flags.StringVar(&options.restartPolicy, "restart", "", "Restart policy to apply when a container exits")
+	flags.Int64Var(&options.pidsLimit, "pids-limit", 0, "Tune container pids limit (set -1 for unlimited)")
+	flags.SetAnnotation("pids-limit", "version", []string{"1.40"})
 
 	flags.Var(&options.cpus, "cpus", "Number of CPUs")
 	flags.SetAnnotation("cpus", "version", []string{"1.29"})
@@ -103,6 +106,10 @@ func runUpdate(dockerCli command.Cli, options *updateOptions) error {
 		NanoCPUs:           options.cpus.Value(),
 	}
 
+	if options.pidsLimit != 0 {
+		resources.PidsLimit = &options.pidsLimit
+	}
+
 	updateConfig := containertypes.UpdateConfig{
 		Resources:     resources,
 		RestartPolicy: restartPolicy,