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Review haproxy SOP

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Signed-off-by: Michal Konečný <mkonecny@redhat.com>
This commit is contained in:
Michal Konečný 2021-09-02 13:17:57 +02:00
parent 3fb039d94f
commit d405e732a6
2 changed files with 23 additions and 27 deletions
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2
modules/sysadmin_guide/nav.adoc
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@ -45,7 +45,7 @@
** xref:greenwave.adoc[Greenwave - SOP]
** xref:guestdisk.adoc[Guest Disk Resize - SOP]
** xref:guestedit.adoc[Guest Editing - SOP]
** xref:haproxy.adoc[haproxy - SOP in review ]
** xref:haproxy.adoc[Haproxy Infrastructure - SOP]
** xref:hotfix.adoc[hotfix - SOP in review ]
** xref:hotness.adoc[hotness - SOP in review ]
** xref:index.adoc[index - SOP in review ]

48
modules/sysadmin_guide/pages/haproxy.adoc
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@ -5,18 +5,17 @@ at the http layer. It can do generic tcp balancing but it does
specialize in http balancing. Our proxy servers are still running apache
and that is what our users connect to. But instead of using
mod_proxy_balancer and ProxyPass balancer://, we do a ProxyPass to
[45]http://localhost:10001/ or [46]http://localhost:10002/. haproxy must
http://localhost:10001/ or http://localhost:10002/. haproxy must
be told to listen to an individual port for each farm. All haproxy farms
are listed in /etc/haproxy/haproxy.cfg.
== Contents
[arabic]
. Contact Information
. How it works
. Configuration example
. Stats
. Advanced Usage
* <<_contact_information>>
* <<_how_it_works>>
* <<_configuration_example>>
* <<_stats>>
* <<_advanced_usage>>
== Contact Information
@ -45,7 +44,6 @@ request 1 goes to app1, request2 goes to app2, request 3 goes to app3
request 4 goes to app1, and the whole process repeats.
[WARNING]
.Warning
====
These checks do add load to the app servers. As well as additional
connections. Be smart about which url you're checking as it gets checked
@ -64,42 +62,40 @@ subtraction of specific nodes when we need them.:
....
listen fpo-wiki 0.0.0.0:10001
balance roundrobin
server app1 app1.fedora.phx.redhat.com:80 check inter 2s rise 2 fall 5
server app2 app2.fedora.phx.redhat.com:80 check inter 2s rise 2 fall 5
server app4 app4.fedora.phx.redhat.com:80 backup check inter 2s rise 2 fall 5
server app1 app1.fedora.iad2.redhat.com:80 check inter 2s rise 2 fall 5
server app2 app2.fedora.iad2.redhat.com:80 check inter 2s rise 2 fall 5
server app4 app4.fedora.iad2.redhat.com:80 backup check inter 2s rise 2 fall 5
option httpchk GET /wiki/Infrastructure
....
* The first line "listen ...." Says to create a farm called 'fpo-wiki'.
Listening on all IP's on port 10001. fpo-wiki can be arbitrary but make
* The first line "listen ...." Says to create a farm called _fpo-wiki_.
Listening on all IP's on port 10001. _fpo-wiki_ can be arbitrary but make
it something obvious. Aside from that the important bit is :10001.
Always make sure that when creating a new farm, its listening on a
unique port. In Fedora's case we're starting at 10001, and moving up by
one. Just check the config file for the lowest open port above 10001.
* The next line "balance roundrobin" says to use round robin balancing.
* The next line _balance roundrobin_ says to use round robin balancing.
* The server lines each add a new node to the balancer farm. In this
case the wiki is being served from app1, app2 and app4. If the wiki is
available at [53]http://app1.fedora.phx.redhat.com/wiki/ Then this
available at http://app1.fedora.iad2.redhat.com/wiki/ Then this
config would be used in conjunction with "RewriteRule ^/wiki/(.*)
[54]http://localhost:10001/wiki/$1 [P,L]".
* 'server' means we're adding a new node to the farm
* {blank}
+
'app1' is the worker name, it is analagous to fpo-wiki but should::
http://localhost:10001/wiki/$1 [P,L]".
* _server_ means we're adding a new node to the farm
* _app1_ is the worker name, it is analagous to fpo-wiki but should::
match shorthostname of the node to make it easy to follow.
* 'app1.fedora.phx.redhat.com:80' is the hostname and port to be
* _app1.fedora.iad2.redhat.com:80_ is the hostname and port to be
contacted.
* 'check' means to check via bottom line "option httpchk GET
* _check_ means to check via bottom line "option httpchk GET
/wiki/Infrastructure" which will use /wiki/Infrastructure to verify the
wiki is working. If that URL fails, that entire node will be taken out
of the farm mix.
* 'inter 2s' means to check every 2 seconds. 2s is the same as 2000 in
* _inter 2s_ means to check every 2 seconds. 2s is the same as 2000 in
this case.
* 'rise 2' means to not put this node back in the mix until it has had
* _rise 2_ means to not put this node back in the mix until it has had
two successful connections in a row. haproxy will continue to check
every 2 seconds whether a node is up or down
* 'fall 5' means to take a node out of the farm after 5 failures.
* 'backup' You'll notice that app4 has a 'backup' option. We don't
* _fall 5_ means to take a node out of the farm after 5 failures.
* _backup_ You'll notice that app4 has a _backup_ option. We don't
actually use this for the wiki but do for other farms. It basically
means to continue checking and treat this node like any other node but
don't send it any production traffic unless the other two nodes are