Add containerd snapshotter flag (#1991)

* Add containerd snapshotter flag

Signed-off-by: Jason-ZW <zhenyang@rancher.com>

* Fix CamelCase nit and option description

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
Signed-off-by: Jason-ZW <zhenyang@rancher.com>

Co-authored-by: Brad Davidson <brad@oatmail.org>

pkg/agent/config/config.go

@@ -423,6 +423,7 @@ func get(envInfo *cmds.Agent, proxy proxy.Proxy) (*config.Node, error) {
 		nodeConfig.AgentConfig.RootDir = filepath.Join(envInfo.DataDir, "kubelet")
 	}
 	nodeConfig.AgentConfig.PauseImage = envInfo.PauseImage
+	nodeConfig.AgentConfig.Snapshotter = envInfo.Snapshotter
 	nodeConfig.AgentConfig.IPSECPSK = controlConfig.IPSECPSK
 	nodeConfig.AgentConfig.StrongSwanDir = filepath.Join(envInfo.DataDir, "strongswan")
 	nodeConfig.CACerts = info.CACerts

pkg/agent/templates/templates.go

@@ -33,6 +33,11 @@ const ContainerdConfigTemplate = `
   sandbox_image = "{{ .NodeConfig.AgentConfig.PauseImage }}"
 {{end}}
 
+{{- if .NodeConfig.AgentConfig.Snapshotter }}
+[plugins.cri.containerd]
+  snapshotter = "{{ .NodeConfig.AgentConfig.Snapshotter }}"
+{{end}}
+
 {{- if not .NodeConfig.NoFlannel }}
 [plugins.cri.cni]
   bin_dir = "{{ .NodeConfig.AgentConfig.CNIBinDir }}"

pkg/cli/cmds/agent.go

@@ -21,6 +21,7 @@ type Agent struct {
 	NodeExternalIP           string
 	NodeName                 string
 	PauseImage               string
+	Snapshotter              string
 	Docker                   bool
 	ContainerRuntimeEndpoint string
 	NoFlannel                bool
@@ -90,6 +91,12 @@ var (
 		Destination: &AgentConfig.PauseImage,
 		Value:       "docker.io/rancher/pause:3.1",
 	}
+	SnapshotterFlag = cli.StringFlag{
+		Name:        "snapshotter",
+		Usage:       "(agent/runtime) Override default containerd snapshotter",
+		Destination: &AgentConfig.Snapshotter,
+		Value:       "overlayfs",
+	}
 	FlannelFlag = cli.BoolFlag{
 		Name:        "no-flannel",
 		Usage:       "(deprecated) use --flannel-backend=none",
@@ -190,6 +197,7 @@ func NewAgentCommand(action func(ctx *cli.Context) error) *cli.Command {
 			&DisableSELinuxFlag,
 			&CRIEndpointFlag,
 			&PauseImageFlag,
+			&SnapshotterFlag,
 			&PrivateRegistryFlag,
 			&NodeIPFlag,
 			&NodeExternalIPFlag,

pkg/cli/cmds/server.go

@@ -238,6 +238,7 @@ func NewServerCommand(action func(*cli.Context) error) *cli.Command {
 			&DisableSELinuxFlag,
 			&CRIEndpointFlag,
 			&PauseImageFlag,
+			&SnapshotterFlag,
 			&PrivateRegistryFlag,
 			&NodeIPFlag,
 			&NodeExternalIPFlag,

pkg/daemons/config/types.go

@@ -72,6 +72,7 @@ type Agent struct {
 	ExtraKubeletArgs        []string
 	ExtraKubeProxyArgs      []string
 	PauseImage              string
+	Snapshotter             string
 	CNIPlugin               bool
 	NodeTaints              []string
 	NodeLabels              []string