From 27ca091c08674b1a34058c9639d60455023ffa30 Mon Sep 17 00:00:00 2001
From: Daniel J Walsh <dwalsh@redhat.com>
Date: Tue, 21 Aug 2018 07:31:00 -0400
Subject: Add proper support for systemd inside of podman
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>
---
cmd/podman/common.go | 4 ++++
cmd/podman/create.go | 15 ++++++++++++++-
completions/bash/podman | 1 +
docs/podman-create.1.md | 13 +++++++++++++
docs/podman-run.1.md | 13 +++++++++++++
pkg/spec/createconfig.go | 7 ++++---
pkg/spec/spec.go | 43 +++++++++++++++++++++++++++++++++++++++++++
7 files changed, 92 insertions(+), 4 deletions(-)
diff --git a/cmd/podman/common.go b/cmd/podman/common.go
index 93b16f4e3..43a0fe061 100644
--- a/cmd/podman/common.go
+++ b/cmd/podman/common.go
@@ -383,6 +383,10 @@ var createFlags = []cli.Flag{
Name: "sysctl",
Usage: "Sysctl options (default [])",
},
+ cli.BoolTFlag{
+ Name: "systemd",
+ Usage: "Run container in systemd mode if the command executable is systemd or init",
+ },
cli.StringSliceFlag{
Name: "tmpfs",
Usage: "Mount a temporary filesystem (`tmpfs`) into a container (default [])",
diff --git a/cmd/podman/create.go b/cmd/podman/create.go
index 209064eff..e7e349306 100644
--- a/cmd/podman/create.go
+++ b/cmd/podman/create.go
@@ -5,6 +5,7 @@ import (
"encoding/json"
"fmt"
"os"
+ "path/filepath"
"strconv"
"strings"
"syscall"
@@ -509,7 +510,7 @@ func parseCreateOpts(ctx context.Context, c *cli.Context, runtime *libpod.Runtim
// STOP SIGNAL
stopSignal := syscall.SIGTERM
- signalString := "SIGTERM"
+ signalString := ""
if data != nil {
signalString = data.ContainerConfig.StopSignal
}
@@ -648,6 +649,17 @@ func parseCreateOpts(ctx context.Context, c *cli.Context, runtime *libpod.Runtim
return nil, errors.Errorf("invalid image-volume type %q. Pick one of bind, tmpfs, or ignore", c.String("image-volume"))
}
+ var systemd bool
+ if c.BoolT("systemd") && ((filepath.Base(command[0]) == "init") || (filepath.Base(command[0]) == "systemd")) {
+ systemd = true
+ if signalString == "" {
+ stopSignal, err = signal.ParseSignal("RTMIN+3")
+ if err != nil {
+ return nil, errors.Wrapf(err, "error parsing systemd signal")
+ }
+ }
+ }
+
config := &cc.CreateConfig{
Runtime: runtime,
Annotations: annotations,
@@ -726,6 +738,7 @@ func parseCreateOpts(ctx context.Context, c *cli.Context, runtime *libpod.Runtim
StopSignal: stopSignal,
StopTimeout: c.Uint("stop-timeout"),
Sysctl: sysctl,
+ Systemd: systemd,
Tmpfs: c.StringSlice("tmpfs"),
Tty: tty,
User: user,
diff --git a/completions/bash/podman b/completions/bash/podman
index 083211fc1..91c08a78c 100644
--- a/completions/bash/podman
+++ b/completions/bash/podman
@@ -1494,6 +1494,7 @@ _podman_container_run() {
--subgidname
--subuidname
--sysctl
+ --systemd
--uidmap
--ulimit
--user -u
diff --git a/docs/podman-create.1.md b/docs/podman-create.1.md
index f27a84b1d..8523d0c78 100644
--- a/docs/podman-create.1.md
+++ b/docs/podman-create.1.md
@@ -544,6 +544,19 @@ Network Namespace - current sysctls allowed:
Note: if you use the --network=host option these sysctls will not be allowed.
+**--systemd**=*true*|*false*
+
+Run container in systemd mode. The default is *true*.
+
+If the command you running inside of the container is systemd or init, podman
+will setup tmpfs mount points in the following directories:
+
+/run, /run/lock, /tmp, /sys/fs/cgroup/systemd, /var/lib/journal
+
+It will also set the default stop signal to SIGRTMIN+3.
+
+This allow systemd to run in a confined container without any modifications.
+
**--tmpfs**=[] Create a tmpfs mount
Mount a temporary filesystem (`tmpfs`) mount into a container, for example:
diff --git a/docs/podman-run.1.md b/docs/podman-run.1.md
index 7b23f356f..59b9d4b01 100644
--- a/docs/podman-run.1.md
+++ b/docs/podman-run.1.md
@@ -578,6 +578,19 @@ Network Namespace - current sysctls allowed:
Note: if you use the `--network=host` option these sysctls will not be allowed.
+**--systemd**=*true*|*false*
+
+Run container in systemd mode. The default is *true*.
+
+If the command you running inside of the container is systemd or init, podman
+will setup tmpfs mount points in the following directories:
+
+/run, /run/lock, /tmp, /sys/fs/cgroup/systemd, /var/lib/journal
+
+It will also set the default stop signal to SIGRTMIN+3.
+
+This allow systemd to run in a confined container without any modifications.
+
**--tmpfs**=[] Create a tmpfs mount
Mount a temporary filesystem (`tmpfs`) mount into a container, for example:
diff --git a/pkg/spec/createconfig.go b/pkg/spec/createconfig.go
index c7eaeb9f7..486281200 100644
--- a/pkg/spec/createconfig.go
+++ b/pkg/spec/createconfig.go
@@ -115,9 +115,10 @@ type CreateConfig struct {
Resources CreateResourceConfig
Rm bool //rm
ShmDir string
- StopSignal syscall.Signal // stop-signal
- StopTimeout uint // stop-timeout
- Sysctl map[string]string //sysctl
+ StopSignal syscall.Signal // stop-signal
+ StopTimeout uint // stop-timeout
+ Sysctl map[string]string //sysctl
+ Systemd bool
Tmpfs []string // tmpfs
Tty bool //tty
UsernsMode container.UsernsMode //userns
diff --git a/pkg/spec/spec.go b/pkg/spec/spec.go
index 26b93f5fe..11bc880cb 100644
--- a/pkg/spec/spec.go
+++ b/pkg/spec/spec.go
@@ -4,6 +4,7 @@ import (
"os"
"strings"
+ "github.com/containers/libpod/libpod"
"github.com/containers/libpod/pkg/rootless"
"github.com/docker/docker/daemon/caps"
"github.com/docker/docker/pkg/mount"
@@ -221,6 +222,12 @@ func CreateConfigToOCISpec(config *CreateConfig) (*spec.Spec, error) { //nolint
}
}
+ if config.Systemd && (strings.HasSuffix(config.Command[0], "init") ||
+ strings.HasSuffix(config.Command[0], "systemd")) {
+ if err := setupSystemd(config, &g); err != nil {
+ return nil, errors.Wrap(err, "failed to setup systemd")
+ }
+ }
for _, i := range config.Tmpfs {
// Default options if nothing passed
options := []string{"rw", "private", "noexec", "nosuid", "nodev", "size=65536k"}
@@ -353,6 +360,42 @@ func blockAccessToKernelFilesystems(config *CreateConfig, g *generate.Generator)
}
}
+// systemd expects to have /run, /run/lock and /tmp on tmpfs
+// It also expects to be able to write to /sys/fs/cgroup/systemd and /var/log/journal
+
+func setupSystemd(config *CreateConfig, g *generate.Generator) error {
+ mounts, err := config.GetVolumeMounts([]spec.Mount{})
+ if err != nil {
+ return err
+ }
+ options := []string{"rw", "private", "noexec", "nosuid", "nodev"}
+ for _, dest := range []string{"/run", "/run/lock", "/sys/fs/cgroup/systemd"} {
+ if libpod.MountExists(mounts, dest) {
+ continue
+ }
+ tmpfsMnt := spec.Mount{
+ Destination: dest,
+ Type: "tmpfs",
+ Source: "tmpfs",
+ Options: append(options, "tmpcopyup", "size=65536k"),
+ }
+ g.AddMount(tmpfsMnt)
+ }
+ for _, dest := range []string{"/tmp", "/var/log/journal"} {
+ if libpod.MountExists(mounts, dest) {
+ continue
+ }
+ tmpfsMnt := spec.Mount{
+ Destination: dest,
+ Type: "tmpfs",
+ Source: "tmpfs",
+ Options: append(options, "tmpcopyup"),
+ }
+ g.AddMount(tmpfsMnt)
+ }
+ return nil
+}
+
func addPidNS(config *CreateConfig, g *generate.Generator) error {
pidMode := config.PidMode
if IsNS(string(pidMode)) {
--
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