Switch default logdriver and eventslogger to journald, if root

[rhatdan]

Signed-off-by: Daniel J Walsh [email protected]

[openshift-ci]

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[rhatdan]

@giuseppe @vrothberg is there an easy way to see if journald will work for rootless users?

[rhatdan]

Attempting to fix/improve #580

[vrothberg]

/hold

Can you open a test PR against Podman? We've had bad experiences in previous attempts. I am optimistic that it'll pass since we massaged the journald backends quite a bit but I want to make sure we merge after Podman CI is green.

[vrothberg]

@giuseppe @vrothberg is there an easy way to see if journald will work for rootless users?

https://github.com/containers/podman/blob/master/pkg/systemd/dbus.go has some code for it. I think that if we can connect to DBUS, we can default to journald.

[rhatdan]

That will tell us we have a dbus connection, but not necessarily if we can write journald messages.

I will open a PR for Podman.

[rhatdan]

Currently this patch just uses file for rootless systems, even if the system supports rootless journald. Since some systems give permission denied if you try to write to the journal without being in the "wheel" group.

[vrothberg]

Good point. There may be group access in between. Then something as below should work:

import "github.com/coreos/go-systemd/v22/sdjournal"

func CanAccessJournald() bool {
   journal, err := sdjournal.NewJournal()
   if err != nil {                       
           logrus.Debugf("Cannot access journald: %v", err)
           return false
   }                         
 return true            
}

[rhatdan]

containers/podman#10653

[vrothberg]

Good point. There may be group access in between. Then something as below should work:

import "github.com/coreos/go-systemd/v22/sdjournal"

func CanAccessJournald() bool {
   journal, err := sdjournal.NewJournal()
   if err != nil {                       
           logrus.Debugf("Cannot access journald: %v", err)
           return false
   }                         
 return true            
}

I think we need to defer journal.Close() as well.

[rhatdan]

This adds a requirement for cgo...

[rhatdan]

 $ make
GOOS=linux GOARCH= go build -tags "" ./... # attempt to build without tags
GOOS=linux GOARCH=386 go build -tags "containers_image_openpgp,systemd" ./...
package github.com/containers/common/libimage
	imports github.com/containers/common/pkg/config
	imports github.com/coreos/go-systemd/v22/sdjournal
	imports github.com/coreos/go-systemd/v22/internal/dlopen: build constraints exclude all Go files in /home/dwalsh/go/src/github.com/containers/common/vendor/github.com/coreos/go-systemd/v22/internal/dlopen
make: *** [Makefile:41: build-cross] Error 1

[vrothberg]

May need to add CGO_ENABLED ?= 1 to the Makefile. Does that resolve the build?

[rhatdan]

That is causing us to pull in lots of other libraries and files including -devmapper.

[rhatdan]

@giuseppe @vrothberg @nalind Do you know if this is enough to check if we can use the journal?

[nalind]

It looks like the implementation will either manage to open the journal for reading and return a handle for it, or return an error. The APIs for sending data to the journal don't go through the handle, so I think we have to take it on faith that messages we send to the journal will be retrievable through the handle.

[rhatdan]

SGTM

[rhatdan]

@TomSweeneyRedHat @mheon PTAL
Have the PR for Podman working now, Would like to get this into RHEL9.

@containers/podman-maintainers PTAL

[jwhonce]

LGTM

[TomSweeneyRedHat]

Should you still set DefaultLogDriver to k8s-file, return it here, and then just system it to systems in the appropriate places?

[rhatdan]

No because we want DefaultLogDriver to be indicated as journald now.

[TomSweeneyRedHat]

LGTM
one question over the default setting.

[vrothberg]

We need to flip back: containers/podman#10653 was not green and it's now causing c/common to break in Podman.

[vrothberg]

We need to flip back: containers/podman#10653 was not green and it's now causing c/common to break in Podman.

Correction. We're good! @nalind is pushing the PR in Podman over the finish line in containers/podman#11263.