Disable healthcheck, missing global config option for systems without systemd

[mluhmann]

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

/kind bug

Description

I have a custom linux build on yocto without systemd and I had to update to podman v4.2.1. But now I am getting lots of errors due to missing systemd like "unable to get systemd connection to add healthchecks". I can work around this with the --no-healthcheck option or disable it in my compose files. But this isn't convenient for legacy containers and developers working with this linux.

Steps to reproduce the issue:

Just start any container on a system without systemd.

Describe the results you received:

Bunch of errors regarding systemd connection not possible.

Describe the results you expected:

Disable healthcheck for my whole linux yocto build by a global config option. No need for --no-healthcheck parameter or comparable for every container.

Output of podman version:

Client: Podman Engine
Version: 4.2.1-dev
API Version: 4.2.1-dev
Go Version: go1.17.13
Git Commit: 754ec89
Built: Tue Aug 16 08:54:44 2022
OS/Arch: linux/arm

Output of podman info:

host:
arch: arm
buildahVersion: 1.27.0
cgroupControllers:

• cpuset
• cpu
• cpuacct
• blkio
• memory
• devices
• freezer
• net_cls
• net_prio
• pids
• rdma
  cgroupManager: cgroupfs
  cgroupVersion: v1
  conmon:
  package: Unknown
  path: /usr/bin/conmon
  version: 'conmon version 2.1.0, commit: 4c41ec2a215c502ad6c38ea255ac1082fa1d381d'
  cpuUtilization:
  idlePercent: 93.96
  systemPercent: 2.79
  userPercent: 3.25
  cpus: 2
  distribution:
  distribution: unknown
  version: unknown
  eventLogger: file
  hostname: host
  idMappings:
  gidmap: null
  uidmap: null
  kernel: 5.4.193-rt74-pxc
  linkmode: dynamic
  logDriver: k8s-file
  memFree: 126357504
  memTotal: 512741376
  networkBackend: cni
  ociRuntime:
  name: runc
  package: Unknown
  path: /usr/bin/runc
  version: |-
  runc version 1.1.2+dev
  commit: v1.1.2-9-gb507e2da-dirty
  spec: 1.0.2-dev
  go: go1.17.13
  libseccomp: 2.5.3
  os: linux
  remoteSocket:
  path: /run/podman/podman.sock
  security:
  apparmorEnabled: false
  capabilities: CAP_CHOWN,CAP_DAC_OVERRIDE,CAP_FOWNER,CAP_FSETID,CAP_KILL,CAP_NET_BIND_SERVICE,CAP_SETFCAP,CAP_SETGID,CAP_SETPCAP,CAP_SETUID,CAP_SYS_CHROOT
  rootless: false
  seccompEnabled: true
  seccompProfilePath: unconfined
  selinuxEnabled: false
  serviceIsRemote: false
  slirp4netns:
  executable: /usr/bin/slirp4netns
  package: Unknown
  version: |-
  slirp4netns version 1.2.0-beta.0+dev
  commit: unknown
  libslirp: 4.6.1.55-888d
  SLIRP_CONFIG_VERSION_MAX: 4
  libseccomp: 2.5.3
  swapFree: 0
  swapTotal: 0
  uptime: 2h 28m 21.00s (Approximately 0.08 days)
  plugins:
  authorization: null
  log:
• k8s-file
• none
• passthrough
  network:
• bridge
• macvlan
• ipvlan
  volume:
• local
  registries:
  '*.docker.io':
  Blocked: false
  Insecure: false
  Location: ""
  MirrorByDigestOnly: false
  Mirrors:
  • Insecure: false
    Location: mirror.gcr.io
    PullFromMirror: ""
  • Insecure: false
    Location: quay.io/libpod
    PullFromMirror: ""
    Prefix: '.docker.io'
    PullFromMirror: ""
    '.fedoraproject.org':
    Blocked: false
    Insecure: false
    Location: registry.fedoraproject.org
    MirrorByDigestOnly: false
    Mirrors: null
    Prefix: '*.fedoraproject.org'
    PullFromMirror: ""
    localhost:5000:
    Blocked: false
    Insecure: true
    Location: localhost:5000
    MirrorByDigestOnly: false
    Mirrors: null
    Prefix: localhost:5000
    PullFromMirror: ""
    search:
• docker.io
• quay.io
• registry.fedoraproject.org
  store:
  configFile: /etc/containers/storage.conf
  containerStore:
  number: 3
  paused: 0
  running: 0
  stopped: 3
  graphDriverName: overlay
  graphOptions:
  overlay.mountopt: nodev
  graphRoot: /media/rfs/rw/data/system/containers
  graphRootAllocated: 7688126464
  graphRootUsed: 778731520
  graphStatus:
  Backing Filesystem: extfs
  Native Overlay Diff: "true"
  Supports d_type: "true"
  Using metacopy: "false"
  imageCopyTmpDir: /media/rfs/rw/data/system/containers/
  imageStore:
  number: 2
  runRoot: /media/rfs/rw/data/system/containers_temp
  volumePath: /media/rfs/rw/data/system/containers/volumes
  version:
  APIVersion: 4.2.1-dev
  Built: 1660640084
  BuiltTime: Tue Aug 16 08:54:44 2022
  GitCommit: 754ec89
  GoVersion: go1.17.13
  Os: linux
  OsArch: linux/arm
  Version: 4.2.1-dev

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

[Luap99]

There is already a (undocumented?) DISABLE_HC_SYSTEMD env var that can be set to true,

podman/libpod/healthcheck.go

Lines 302 to 305 in 5908996

	func (c *Container) disableHealthCheckSystemd() bool {
	if os.Getenv("DISABLE_HC_SYSTEMD") == "true" {
	return true
	}

However I wonder why this should be needed in the first place? IMO if there is no systemd present we should just ignore healthchecks.

We could also use the systemd build tag to disable it at build time if the tag is not set.

[vrothberg]

However I wonder why this should be needed in the first place? IMO if there is no systemd present we should just ignore healthchecks.

I agree, and also like the idea of the build tag.

[davdr]

Also relevant when running Podman under WSL2 (other then Podman's own podman-machine, which adds a separate namespace to be able to run sytemd when you normally can't).