5:40 a.m.
On Mon, Jan 17, 2022 at 04:39:16PM +0100, Peter Krempa wrote:
Modular daemons are now the default in many new installations, thus
we
need to include steps how to determine that modular daemons are used and
modular-daemon specific locations for the config files and admin URIs.
Signed-off-by: Peter Krempa <pkrempa(a)redhat.com>
---
docs/kbase/debuglogs.rst | 94 +++++++++++++++++++++++++++++++---------
1 file changed, 73 insertions(+), 21 deletions(-)
diff --git a/docs/kbase/debuglogs.rst b/docs/kbase/debuglogs.rst
index fc75ef14a4..ea7c2c1d52 100644
--- a/docs/kbase/debuglogs.rst
+++ b/docs/kbase/debuglogs.rst
@@ -87,38 +87,87 @@ more information than lack something important.
Libvirt daemons logging configuration
=====================================
-Persistent setting
-------------------
+Libvirt daemons can be configured either via a config file or via the
+administration API. The configuration location depends on multiple factors.
-The daemon configuration files location is dependent on `connection
-URI <https://libvirt.org/uri.html>`__. For ``qemu:///system``:
+Session vs. system daemons
+--------------------------
s/\.//
+The libvirt daemons run either on ``system`` level or on ``session`` (user)
s/^The//
s/on/in the/g
s/level/mode/g
+level, depending on the configuration of the host and the available
permission
+levels.
s/the available/available/
+The `connection URI <https://libvirt.org/uri.html>`__ influences which daemon
+the client is communicating with.
s/is communicating/will communicate with
"A few facts about the two runtime modes"
-- open ``/etc/libvirt/libvirtd.conf`` in your favourite editor
-- find & replace, or set these variables:
+``system`` daemon e.g ``qemu:///system`` URI
-::
+ * config files are usually placed in ``/etc/libvirt/``
- log_filters="3:remote 4:event 3:util.json 3:rpc 1:*"
- log_outputs="1:file:/var/log/libvirt/libvirtd.log"
+ * ``virt-admin`` URI ending in ``/system`` should be used.
-- save and exit
-- restart libvirtd service
There should be a subsubsection for both IMO, how about:
"System mode
- all connection URIs will end with '/system', e.g. ``qemu:///system```
- config files are usually placed..."
I deliberately left out the virt-admin part, because you're mentioning it again
in 'Modular vs monolithic daemons', it's enough if virt-admin is mentioned
once
only.
...analogically, the same apples to the 'session' mode section below...
+``session`` daemon e.g. ``qemu:///session`` URI
-::
+ * config files are usually placed in ``$XDG_CONFIG_HOME/libvirt/`` directory
+
+ * ``virt-admin`` URI ending in ``/session`` should be used
+
+Modular vs. monolithic daemons
+------------------------------
+
+While the config file name for the monolithic daemon is simple, in case when
+modular daemons are used, there's a lot of options.
+
+All libvirt daemons support the logging configuration per this document, but
+in most cases it's required to configure logging for the appropriate.
How about:
"While there is only a single 'libvirtd.conf' configuration file in case of
the
monolithic daemon setup, each of the modular daemons has their own
configuration file giving you a lot of possibilities how to configure them
individually including logging. Realistically though, logging will have to be
configured only for a single or a couple of daemons in case debug logs are
requested."
+
+Refer to `documentation about daemons
<../daemons.html#checking-whether-modular-monolithic-mode-is-in-use>`__
+to figure out which is in use by your system.
+
+ Modular daemons
Same as with system vs session --> should be a subsubsection
+
+ The configuration of modular daemons is in file named after the daemon. E.g.
+ for ``qemu:///system`` connection this is the ``virtqemud`` daemon and
+ correspondingly:
How about:
"Configuration files in the modular daemons setup are named after individual
daemons, each prefixed with 'virt', e.g. in case of the ``qemu:///system``
hypervisor connection, the underlying daemon handling it is called
``virtqemud`` and so the configuration file will be named ``virtqemud.conf``.
For runtime configuration with ``virt-admin`` (see below)
``virtqemud:///system`` or ``virtqemud:///session`` URIs would be used
depending on which runtime mode is used for the daemons (see above)."
...analogically, you can use the same with a few changes for the monolithic
subsection...
+
+ * ``virtqemud.conf`` config file is used
+
+ * ``virtqemud:///system`` or ``virtqemud:///session`` admin URI is used
- systemctl restart libvirtd.service
+ Monolithic daemon
+
+ * ``libvirtd.conf`` config file is used
+
+ * ``libvirtd:///system`` or ``libvirtd:///session`` admin URI is used
+ when the modular qemu hypervisor driver ``virtqemud``
+
+Persistent setting
+------------------
+
"In order to setup libvirt logging persistently, follow the steps
below:"
+- open the appropriate daemon config file in your favourite editor
::
+
+ /etc/libvirt/virtqemud.conf
+ /etc/libvirt/libvirtd.conf
+ $XDG_CONFIG_HOME/libvirt/libvirtd.conf
+ $XDG_CONFIG_HOME/libvirt/virtqemud.conf
+
+- find & replace, or set the apropriate `Log outputs`_ and `Log filters`_, e.g ::
+
+ log_filters="3:remote 4:event 3:util.json 3:rpc 1:*"
+ log_outputs="1:file:/var/log/libvirt/libvirtd.log"
+
+- save and exit
+- restart the corresponding service/daemon e.g. ::
+
+ systemctl restart virtqemud.socket
+ systemctl restart libvirtd.socket
+ systemctl restart libvirtd.service
*Note:* Libvirt prior to the ``libvirt-4.4.0`` release didn't support globbing
patterns and thus requires more configuration. See
`Legacy (pre-4.4.0) libvirt daemon logging configuration`_.
-However, when you are using the session mode ``qemu:///session`` or you run the
-``libvirtd`` as unprivileged user you will find configuration file under
-``$XDG_CONFIG_HOME/libvirt/libvirtd.conf``.
-
Runtime setting
---------------
@@ -127,13 +176,16 @@ after the daemon restarts, since the new session can make the
anomaly
"disappear". Therefore, it's possible to enable the debug logs during
runtime
using libvirt administration API. To use it conveniently, there's the
``virt-admin`` client provided by the ``libvirt-admin`` package. Use the
-package manager provided by your distribution to install this package. Once you
-have it installed, run the following as root to see the set of log filters
-currently being active:
+package manager provided by your distribution to install this package.
+
+**Important**: Substitute ``virt-admin -c $ADMIN_URI`` per above guidance in
s/per above/according to the guideline in the sections above
+place of ``virt-admin`` in the examples below if needed.
+
+The following command allows to query the list of log filters currently active:
"...list of currently active log filters:"
Erik