openstack/octavia
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Improve documentation about log offloading

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Parts of the documentation about log offloading repeated itself.
I added a new "Failover Considerations" section that focuses on that
topic specifically. Therefore, other sections no longer need to show
multi-server configurations.
The new section contains recommendations about
log_retry_count and log_retry_interval values for failover
configurations as well.

Story: 2009876
Task: 44599
Change-Id: If71fce80329fe772c8248bc2eb4445ea15680c5d
This commit is contained in:
Tom Weininger 2022-03-04 16:08:19 +01:00
parent 1bc108b19f
commit 911300d688
1 changed files with 45 additions and 24 deletions
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69
doc/source/admin/log-offloading.rst
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@ -49,15 +49,9 @@ Enabling Administrative Log Offloading
One or more syslog receiver endpoints must be configured in the Octavia
configuration file to enable administrative log offloading. The first endpoint
will be the primary endpoint to receive the syslog packets. Should the first
endpoint become unavailable, the additional endpoints listed will be tried
one at a time.
.. note::
Secondary syslog endpoints will only be used if the log_protocol is
configured for TCP. With the UDP syslog protocol, rsyslog is unable
to detect if the primary endpoint has failed.
will be the primary endpoint to receive the syslog packets.
Read the :ref:`rsyslog failover considerations` section for information about
how to use multiple target servers.
To configure administrative log offloading, set the following setting in your
Octavia configuration file for all of the controllers and restart them:
@ -65,10 +59,10 @@ Octavia configuration file for all of the controllers and restart them:
.. code-block:: ini
[amphora_agent]
admin_log_targets = 192.0.2.1:10514, 2001:db8:1::10:10514
admin_log_targets = 192.0.2.1:10514
In this example, the primary syslog receiver will be 192.0.2.1 on port 10514.
The backup syslog receiver will be 2001:db8:1::10 on port 10514.
In this example, the syslog receiver will be 192.0.2.1 on port 10514.
If *log_protocol* is not specified UDP will be used.
.. note::
@ -122,10 +116,11 @@ Enabling Tenant Flow Log Offloading
One or more syslog receiver endpoints must be configured in the Octavia
configuration file to enable tenant flow log offloading. The first endpoint
will be the primary endpoint to receive the syslog packets. Should the first
endpoint become unavailable, the additional endpoints listed will be tried
one at a time. The endpoints configured for tenant flow log offloading may be
will be the primary endpoint to receive the syslog packets.
The endpoints configured for tenant flow log offloading may be
the same endpoints as the administrative log offloading configuration.
Read the :ref:`rsyslog failover considerations` section for information
about how to use multiple target servers.
.. warning::
@ -136,22 +131,16 @@ the same endpoints as the administrative log offloading configuration.
receivers appropriately based on the expected number of connections your
load balancers will be handling.
.. note::
Secondary syslog endpoints will only be used if the log_protocol is
configured for TCP. With the UDP syslog protocol, rsyslog is unable
to detect if the primary endpoint has failed.
To configure tenant flow log offloading, set the following setting in your
Octavia configuration file for all of the controllers and restart them:
.. code-block:: ini
[amphora_agent]
tenant_log_targets = 192.0.2.1:10514, 2001:db8:1::10:10514
tenant_log_targets = 192.0.2.1:10514
In this example, the primary syslog receiver will be 192.0.2.1 on port 10514.
The backup syslog receiver will be 2001:db8:1::10 on port 10514.
In this example, the syslog receiver will be 192.0.2.1 on port 10514.
If *log_protocol* is not specified UDP will be used.
.. note::
@ -218,6 +207,38 @@ Octavia configuration file for all of the controllers and restart them:
[haproxy_amphora]
user_log_format = '{{ project_id }} {{ lb_id }} %f %ci %cp %t %{+Q}r %ST %B %U %[ssl_c_verify] %{+Q}[ssl_c_s_dn] %b %s %Tt %tsc'
.. _rsyslog failover considerations:
Failover Considerations
=======================
In order to provide protection against potential data loss because of
downtime of a single syslog server, it may be a advisable to
use multiple log targets.
In such configuration *log_protocol* needs to be set to *TCP*.
With the UDP syslog protocol, RSyslog is unable
to detect if the primary endpoint has failed.
Also pay attention to the *log_retry_count* and *log_retry_interval* settings
when using multiple log targets. You might want to set *log_retry_count* to 0
and use a higher value for *log_retry_interval*. Values up to 1800 (30 minutes)
are possible.
That way the failover will happen immediately after the client detects
that the server became unavailable. In such case, that server won't be
used again for at least *log_retry_interval* seconds after that event.
In the following example the primary syslog receiver will be
192.0.2.1 on port 10514.
The backup syslog receiver will be 2001:db8:1::10 on port 10514.
.. code-block:: ini
[amphora_agent]
admin_log_targets = 192.0.2.1:10514, 2001:db8:1::10:10514
tenant_log_targets = 192.0.2.1:10514, 2001:db8:1::10:10514
log_protocol = TCP
log_retry_count = 0
log_retry_interval = 1800
Disabling Logging
=================