unistack-org/cloudinit
4
0
Fork 0
Code Issues 1 Pull Requests Packages Projects Releases Wiki Activity

fix(systemd): remove any existing unit when calling mask

Browse Source
This commit is contained in:
Jonathan Boulle 2014-05-21 11:03:52 -07:00
parent e317c7eb9a
commit 786e4bef65
3 changed files with 34 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Documentation/cloud-config.md
View File

@ -123,6 +123,7 @@ The `coreos.units.*` parameters define a list of arbitrary systemd units to star
- **enable**: Boolean indicating whether or not to handle the [Install] section of the unit file. This is similar to running `systemctl enable <name>`. Default value is false.
- **content**: Plaintext string representing entire unit file. If no value is provided, the unit is assumed to exist already.
- **command**: Command to execute on unit: start, stop, reload, restart, try-restart, reload-or-restart, reload-or-try-restart. Default value is restart.
- **mask**: Whether to mask the unit file by symlinking it to `/dev/null` (analogous to `systemctl mask <name>`). Note that unlike `systemctl mask`, **this will destructively remove any existing unit file** located at `/etc/systemd/system/<unit>`, to ensure that the mask succeeds. Default value is false.
**NOTE:** The command field is ignored for all network, netdev, and link units. The systemd-networkd.service unit will be restarted in their place.

10
system/systemd.go
View File

@ -179,9 +179,17 @@ func MachineID(root string) string {
return id
}
// MaskUnit masks a Unit by the given name by symlinking its unit file (in
// /etc/systemd/system) to /dev/null, analogous to `systemctl mask`
// N.B.: Unlike `systemctl mask`, this function will *remove any existing unit
// file* in /etc/systemd/system, to ensure that the mask will succeed.
func MaskUnit(unit string, root string) error {
masked := path.Join(root, "etc", "systemd", "system", unit)
if err := os.MkdirAll(path.Dir(masked), os.FileMode(0755)); err != nil {
if _, err := os.Stat(masked); os.IsNotExist(err) {
if err := os.MkdirAll(path.Dir(masked), os.FileMode(0755)); err != nil {
return err
}
} else if err := os.Remove(masked); err != nil {
return err
}
return os.Symlink("/dev/null", masked)

31
system/systemd_test.go
View File

@ -154,16 +154,33 @@ func TestMaskUnit(t *testing.T) {
t.Fatalf("Unable to create tempdir: %v", err)
}
defer os.RemoveAll(dir)
if err := MaskUnit("foo.service", dir); err != nil {
t.Fatalf("Unable to mask unit: %v", err)
}
fullPath := path.Join(dir, "etc", "systemd", "system", "foo.service")
target, err := os.Readlink(fullPath)
// Ensure mask works with units that do not currently exist
if err := MaskUnit("foo.service", dir); err != nil {
t.Fatalf("Unable to mask new unit: %v", err)
}
fooPath := path.Join(dir, "etc", "systemd", "system", "foo.service")
fooTgt, err := os.Readlink(fooPath)
if err != nil {
t.Fatalf("Unable to read link", err)
}
if target != "/dev/null" {
t.Fatalf("unit not masked, got unit target", target)
if fooTgt != "/dev/null" {
t.Fatalf("unit not masked, got unit target", fooTgt)
}
// Ensure mask works with unit files that already exist
barPath := path.Join(dir, "etc", "systemd", "system", "bar.service")
if _, err := os.Create(barPath); err != nil {
t.Fatalf("Error creating new unit file: %v", err)
}
if err := MaskUnit("bar.service", dir); err != nil {
t.Fatalf("Unable to mask existing unit: %v", err)
}
barTgt, err := os.Readlink(barPath)
if err != nil {
t.Fatalf("Unable to read link", err)
}
if barTgt != "/dev/null" {
t.Fatalf("unit not masked, got unit target", barTgt)
}
}