--systemd=true auto-detection should consider /usr/local/sbin/init

[tiran]

Is this a BUG REPORT or FEATURE REQUEST? (leave only one on its own line)

/kind bug

Description

podman run defaults to --systemd=true. With --systemd=true podman checks whether the command is either /sbin/init, /usr/sbin/init, or systemd.

podman/pkg/specgen/generate/container_create.go

Lines 166 to 170 in a90ae00

	if len(command) > 0 {
	if command[0] == "/usr/sbin/init" || command[0] == "/sbin/init" || (filepath.Base(command[0]) == "systemd") {
	useSystemd = true
	}
	}

The check was introduced in podman 1.6.2. Previously podman only checked that the command ended in init or systemd. The change broke FreeIPA container. Our containes uses a custom shell script at /usr/local/sbin/init that prepares the system and then execs systemd at /sbin/init. The container used to run fine with older versions of podman. It took our team a while to realize that more recent versions of podman no longer active systemd support with --systemd=true for our container. We thought that --systemd=true always activates systemd support. At first it didn't occur to us that it merely activates systemd detection mode. @frasertweedale eventually connected the dots when he saw a BZ comment with --systemd=always.

Steps to reproduce the issue:

1. sudo podman run --rm --name freeipa-server-container -ti -h ipa.example.test --sysctl net.ipv6.conf.all.disable_ipv6=0 -v /var/lib/ipa-data:/data:Z -v /etc/machine-id:/etc/machine-id:ro --read-only --systemd=true freeipa-server

Describe the results you received:

Container fails to start with error message:

systemd v245.7-1.fc32 running in system mode. (+PAM +AUDIT +SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN +PCRE2 default-hierarchy=unified)
Detected virtualization podman.
Detected architecture x86-64.
Set hostname to <ipa.example.test>.
Failed to create /init.scope control group: Read-only file system
Failed to allocate manager object: Read-only file system
[!!!!!!] Failed to allocate manager object.
Exiting PID 1...

Describe the results you expected:

FreeIPA container should start and work.

Additional information you deem important (e.g. issue happens only occasionally):

The container starts correctly with --systemd=always.

Please extend systemd auto-detection to include /usr/local/sbin/init. It would also be helpful to print a debug message whether podman has detected systemd or not.

Output of podman version:

Version:      2.0.4
API Version:  1
Go Version:   go1.14.6
Built:        Thu Jan  1 01:00:00 1970
OS/Arch:      linux/amd64

1.6.4 is also affected

Package info (e.g. output of rpm -q podman or apt list podman):

podman-2.0.4-1.fc32.x86_64

Additional environment details (AWS, VirtualBox, physical, etc.):

n/a/