[PATCH] remote: systemd: Remove unix sockets from filesystem when disabling a '.socket' unit
The existence of the unix socket path is used by the remote driver to determine whether modular daemons are in use, so if the socket file stays behind and the user decided to switch from modular to monolithic daemon which was socket activated, the remote driver will insist on picking '/var/run/libvirt/virtqemud-sock', even when it's no longer in use: # systemctl start libvirtd.service # virsh list Id Name State -------------------- # systemctl stop libvirtd.service Warning: Stopping libvirtd.service, but it can still be activated by: libvirtd.socket libvirtd-ro.socket libvirtd-admin.socket # systemctl start virtqemud.socket # virsh list Id Name State -------------------- # systemctl stop virtqemud.socket # systemctl start libvirtd.service # virsh list error: failed to connect to the hypervisor error: Failed to connect socket to '/var/run/libvirt/virtqemud-sock': Connection refused # virsh -c 'qemu:///system?socket=/var/run/libvirt/libvirt-sock' list Id Name State -------------------- Fix this by instructing systemd to delete the socket file when deactivating the unit file for the socket. Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- src/remote/libvirtd.socket.in | 1 + 1 file changed, 1 insertion(+) diff --git a/src/remote/libvirtd.socket.in b/src/remote/libvirtd.socket.in index 85b4aa800a..0f349656f5 100644 --- a/src/remote/libvirtd.socket.in +++ b/src/remote/libvirtd.socket.in @@ -9,6 +9,7 @@ Before=@service@.service ListenStream=@runstatedir@/libvirt/@sockprefix@-sock Service=@service@.service SocketMode=@mode@ +RemoveOnStop=yes [Install] WantedBy=sockets.target -- 2.34.1
On 1/18/22 15:38, Peter Krempa wrote:
The existence of the unix socket path is used by the remote driver to determine whether modular daemons are in use, so if the socket file stays behind and the user decided to switch from modular to monolithic daemon which was socket activated, the remote driver will insist on picking '/var/run/libvirt/virtqemud-sock', even when it's no longer in use:
# systemctl start libvirtd.service # virsh list Id Name State --------------------
# systemctl stop libvirtd.service Warning: Stopping libvirtd.service, but it can still be activated by: libvirtd.socket libvirtd-ro.socket libvirtd-admin.socket # systemctl start virtqemud.socket # virsh list Id Name State --------------------
# systemctl stop virtqemud.socket # systemctl start libvirtd.service # virsh list error: failed to connect to the hypervisor error: Failed to connect socket to '/var/run/libvirt/virtqemud-sock': Connection refused
# virsh -c 'qemu:///system?socket=/var/run/libvirt/libvirt-sock' list Id Name State --------------------
Fix this by instructing systemd to delete the socket file when deactivating the unit file for the socket.
Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- src/remote/libvirtd.socket.in | 1 + 1 file changed, 1 insertion(+)
diff --git a/src/remote/libvirtd.socket.in b/src/remote/libvirtd.socket.in index 85b4aa800a..0f349656f5 100644 --- a/src/remote/libvirtd.socket.in +++ b/src/remote/libvirtd.socket.in @@ -9,6 +9,7 @@ Before=@service@.service ListenStream=@runstatedir@/libvirt/@sockprefix@-sock Service=@service@.service SocketMode=@mode@ +RemoveOnStop=yes
I beg your pardon? Systemd leaves a stale socket behind? Isn't this something that systemd needs to fix? Michal
On Tue, Jan 18, 2022 at 15:51:21 +0100, Michal Prívozník wrote:
On 1/18/22 15:38, Peter Krempa wrote:
[...]
diff --git a/src/remote/libvirtd.socket.in b/src/remote/libvirtd.socket.in index 85b4aa800a..0f349656f5 100644 --- a/src/remote/libvirtd.socket.in +++ b/src/remote/libvirtd.socket.in @@ -9,6 +9,7 @@ Before=@service@.service ListenStream=@runstatedir@/libvirt/@sockprefix@-sock Service=@service@.service SocketMode=@mode@ +RemoveOnStop=yes
I beg your pardon? Systemd leaves a stale socket behind? Isn't this something that systemd needs to fix?
Well, for that exact reason, they provide a config setting in the unit file that instruts systemd to delete the socket file when the socket unit is stopped, and also the exact reason I'm enabling that setting.
On 1/18/22 15:56, Peter Krempa wrote:
On Tue, Jan 18, 2022 at 15:51:21 +0100, Michal Prívozník wrote:
On 1/18/22 15:38, Peter Krempa wrote:
[...]
diff --git a/src/remote/libvirtd.socket.in b/src/remote/libvirtd.socket.in index 85b4aa800a..0f349656f5 100644 --- a/src/remote/libvirtd.socket.in +++ b/src/remote/libvirtd.socket.in @@ -9,6 +9,7 @@ Before=@service@.service ListenStream=@runstatedir@/libvirt/@sockprefix@-sock Service=@service@.service SocketMode=@mode@ +RemoveOnStop=yes
I beg your pardon? Systemd leaves a stale socket behind? Isn't this something that systemd needs to fix?
Well, for that exact reason, they provide a config setting in the unit file that instruts systemd to delete the socket file when the socket unit is stopped, and also the exact reason I'm enabling that setting.
That's one of the worst possible defaults I've sever seen. If anything, units should have been given an option to opt out, not opt in. But fixing bugs in their respective components instead of libvirt is what we do (I'm looking at you glib). Reviewed-by: Michal Privoznik <mprivozn@redhat.com> Michal
On Tue, Jan 18, 2022 at 03:51:21PM +0100, Michal Prívozník wrote:
On 1/18/22 15:38, Peter Krempa wrote:
The existence of the unix socket path is used by the remote driver to determine whether modular daemons are in use, so if the socket file stays behind and the user decided to switch from modular to monolithic daemon which was socket activated, the remote driver will insist on picking '/var/run/libvirt/virtqemud-sock', even when it's no longer in use:
# systemctl start libvirtd.service # virsh list Id Name State --------------------
# systemctl stop libvirtd.service Warning: Stopping libvirtd.service, but it can still be activated by: libvirtd.socket libvirtd-ro.socket libvirtd-admin.socket # systemctl start virtqemud.socket # virsh list Id Name State --------------------
# systemctl stop virtqemud.socket # systemctl start libvirtd.service # virsh list error: failed to connect to the hypervisor error: Failed to connect socket to '/var/run/libvirt/virtqemud-sock': Connection refused
# virsh -c 'qemu:///system?socket=/var/run/libvirt/libvirt-sock' list Id Name State --------------------
Fix this by instructing systemd to delete the socket file when deactivating the unit file for the socket.
Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- src/remote/libvirtd.socket.in | 1 + 1 file changed, 1 insertion(+)
diff --git a/src/remote/libvirtd.socket.in b/src/remote/libvirtd.socket.in index 85b4aa800a..0f349656f5 100644 --- a/src/remote/libvirtd.socket.in +++ b/src/remote/libvirtd.socket.in @@ -9,6 +9,7 @@ Before=@service@.service ListenStream=@runstatedir@/libvirt/@sockprefix@-sock Service=@service@.service SocketMode=@mode@ +RemoveOnStop=yes
I beg your pardon? Systemd leaves a stale socket behind? Isn't this something that systemd needs to fix?
Michal
On Tue, Jan 18, 2022 at 03:51:21PM +0100, Michal Prívozník wrote:
On 1/18/22 15:38, Peter Krempa wrote:
The existence of the unix socket path is used by the remote driver to determine whether modular daemons are in use, so if the socket file stays behind and the user decided to switch from modular to monolithic daemon which was socket activated, the remote driver will insist on picking '/var/run/libvirt/virtqemud-sock', even when it's no longer in use:
# systemctl start libvirtd.service # virsh list Id Name State --------------------
# systemctl stop libvirtd.service Warning: Stopping libvirtd.service, but it can still be activated by: libvirtd.socket libvirtd-ro.socket libvirtd-admin.socket # systemctl start virtqemud.socket # virsh list Id Name State --------------------
# systemctl stop virtqemud.socket # systemctl start libvirtd.service # virsh list error: failed to connect to the hypervisor error: Failed to connect socket to '/var/run/libvirt/virtqemud-sock': Connection refused
# virsh -c 'qemu:///system?socket=/var/run/libvirt/libvirt-sock' list Id Name State --------------------
Fix this by instructing systemd to delete the socket file when deactivating the unit file for the socket.
Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- src/remote/libvirtd.socket.in | 1 + 1 file changed, 1 insertion(+)
diff --git a/src/remote/libvirtd.socket.in b/src/remote/libvirtd.socket.in index 85b4aa800a..0f349656f5 100644 --- a/src/remote/libvirtd.socket.in +++ b/src/remote/libvirtd.socket.in @@ -9,6 +9,7 @@ Before=@service@.service ListenStream=@runstatedir@/libvirt/@sockprefix@-sock Service=@service@.service SocketMode=@mode@ +RemoveOnStop=yes
I beg your pardon? Systemd leaves a stale socket behind? Isn't this something that systemd needs to fix?
I was surprised but their justification is: "Normally, it should not be necessary to use this option, and is not recommended as services might continue to run after the socket unit has been terminated and it should still be possible to communicate with them via their file system node. Defaults to off." I would have some agreement with that view if it were possible to then start the .socket unit again, and still connect to the .service. Starting the .socket, however, does an implicit delete. So leaving the socket on disk is only useful if you want to stop the .socket, but never start it again. On balance I think libvirt's need to distinguish daemons is more important, unless we change the probing logic to actually try a connect() but I wasn't too enthusiastic about doing that. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
On Tue, Jan 18, 2022 at 03:38:26PM +0100, Peter Krempa wrote:
The existence of the unix socket path is used by the remote driver to determine whether modular daemons are in use, so if the socket file stays behind and the user decided to switch from modular to monolithic daemon which was socket activated, the remote driver will insist on picking '/var/run/libvirt/virtqemud-sock', even when it's no longer in use:
# systemctl start libvirtd.service # virsh list Id Name State --------------------
# systemctl stop libvirtd.service Warning: Stopping libvirtd.service, but it can still be activated by: libvirtd.socket libvirtd-ro.socket libvirtd-admin.socket # systemctl start virtqemud.socket # virsh list Id Name State --------------------
# systemctl stop virtqemud.socket # systemctl start libvirtd.service # virsh list error: failed to connect to the hypervisor error: Failed to connect socket to '/var/run/libvirt/virtqemud-sock': Connection refused
# virsh -c 'qemu:///system?socket=/var/run/libvirt/libvirt-sock' list Id Name State --------------------
Fix this by instructing systemd to delete the socket file when deactivating the unit file for the socket.
Signed-off-by: Peter Krempa <pkrempa@redhat.com> ---
Yes, please, I've hit this a few times already in the past couple of days. However - the service may still remain running when you stop the socket and as the man page states, it should still be possible to communicate with the service via the filesystem node, e.g. doing 'virsh list'. But I agree this is very annoying and I don't particularly like wiping /run/libvirt whenever I want to switch :( . Erik I'm still inclined to ACK the patch though...
On Tue, 18 Jan 2022, Peter Krempa wrote:
The existence of the unix socket path is used by the remote driver to determine whether modular daemons are in use, so if the socket file stays behind and the user decided to switch from modular to monolithic daemon which was socket activated, the remote driver will insist on picking '/var/run/libvirt/virtqemud-sock', even when it's no longer in use:
# systemctl start libvirtd.service # virsh list Id Name State --------------------
# systemctl stop libvirtd.service Warning: Stopping libvirtd.service, but it can still be activated by: libvirtd.socket libvirtd-ro.socket libvirtd-admin.socket # systemctl start virtqemud.socket # virsh list Id Name State --------------------
# systemctl stop virtqemud.socket # systemctl start libvirtd.service # virsh list error: failed to connect to the hypervisor error: Failed to connect socket to '/var/run/libvirt/virtqemud-sock': Connection refused
# virsh -c 'qemu:///system?socket=/var/run/libvirt/libvirt-sock' list Id Name State --------------------
Fix this by instructing systemd to delete the socket file when deactivating the unit file for the socket.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ani Sinha <ani@anisinha.ca>
--- src/remote/libvirtd.socket.in | 1 + 1 file changed, 1 insertion(+)
diff --git a/src/remote/libvirtd.socket.in b/src/remote/libvirtd.socket.in index 85b4aa800a..0f349656f5 100644 --- a/src/remote/libvirtd.socket.in +++ b/src/remote/libvirtd.socket.in @@ -9,6 +9,7 @@ Before=@service@.service ListenStream=@runstatedir@/libvirt/@sockprefix@-sock Service=@service@.service SocketMode=@mode@ +RemoveOnStop=yes
[Install] WantedBy=sockets.target -- 2.34.1
participants (5)
-
Ani Sinha -
Daniel P. Berrangé -
Erik Skultety -
Michal Prívozník -
Peter Krempa