Healthcheck middleware plugins¶
- class oslo_middleware.healthcheck.Healthcheck(*args, **kwargs)¶
Healthcheck application used for monitoring.
It will respond 200 with “OK” as the body. Or a 503 with the reason as the body if one of the backends reports an application issue.
This is useful for the following reasons:
Load balancers can ‘ping’ this url to determine service availability.
Provides an endpoint that is similar to ‘mod_status’ in apache which can provide details (or no details, depending on if configured) about the activity of the server.
(and more)
Note
This middleware indicates that the API is accessible but it does indicate that it is necessarily functional or that any other API request will actually work.
Example requests/responses (not detailed mode):
$ curl -i -X HEAD "http://0.0.0.0:8775/healthcheck" HTTP/1.1 204 No Content Content-Type: text/plain; charset=UTF-8 Content-Length: 0 Date: Fri, 11 Sep 2015 18:55:08 GMT $ curl -i -X GET "http://0.0.0.0:8775/healthcheck" HTTP/1.1 200 OK Content-Type: text/plain; charset=UTF-8 Content-Length: 2 Date: Fri, 11 Sep 2015 18:55:43 GMT OK $ curl -X GET -i -H "Accept: application/json" "http://0.0.0.0:8775/healthcheck" HTTP/1.0 200 OK Date: Wed, 24 Aug 2016 06:09:58 GMT Content-Type: application/json Content-Length: 63 { "detailed": false, "reasons": [ "OK" ] } $ curl -X GET -i -H "Accept: text/html" "http://0.0.0.0:8775/healthcheck" HTTP/1.0 200 OK Date: Wed, 24 Aug 2016 06:10:42 GMT Content-Type: text/html; charset=UTF-8 Content-Length: 239 <HTML> <HEAD><TITLE>Healthcheck Status</TITLE></HEAD> <BODY> <H2>Result of 1 checks:</H2> <TABLE bgcolor="#ffffff" border="1"> <TBODY> <TR> <TH> Reason </TH> </TR> <TR> <TD>OK</TD> </TR> </TBODY> </TABLE> <HR></HR> </BODY>Example requests/responses (detailed mode):
$ curl -X GET -i -H "Accept: application/json" "http://0.0.0.0:8775/healthcheck" HTTP/1.0 200 OK Date: Wed, 24 Aug 2016 06:11:59 GMT Content-Type: application/json Content-Length: 3480 { "detailed": true, "gc": { "counts": [ 293, 10, 5 ], "threshold": [ 700, 10, 10 ] }, "greenthreads": [ ... ], "now": "2016-08-24 06:11:59.419267", "platform": "Linux-4.2.0-27-generic-x86_64-with-Ubuntu-14.04-trusty", "python_version": "2.7.6 (default, Jun 22 2015, 17:58:13) \n[GCC 4.8.2]", "reasons": [ { "class": "HealthcheckResult", "details": "Path '/tmp/dead' was not found", "reason": "OK" } ], "threads": [ ... ] } $ curl -X GET -i -H "Accept: text/html" "http://0.0.0.0:8775/healthcheck" HTTP/1.0 200 OK Date: Wed, 24 Aug 2016 06:36:07 GMT Content-Type: text/html; charset=UTF-8 Content-Length: 6838 <HTML> <HEAD><TITLE>Healthcheck Status</TITLE></HEAD> <BODY> <H1>Server status</H1> <B>Server hostname:</B><PRE>...</PRE> <B>Current time:</B><PRE>2016-08-24 06:36:07.302559</PRE> <B>Python version:</B><PRE>2.7.6 (default, Jun 22 2015, 17:58:13) [GCC 4.8.2]</PRE> <B>Platform:</B><PRE>Linux-4.2.0-27-generic-x86_64-with-Ubuntu-14.04-trusty</PRE> <HR></HR> <H2>Garbage collector:</H2> <B>Counts:</B><PRE>(77, 1, 6)</PRE> <B>Thresholds:</B><PRE>(700, 10, 10)</PRE> <HR></HR> <H2>Result of 1 checks:</H2> <TABLE bgcolor="#ffffff" border="1"> <TBODY> <TR> <TH> Kind </TH> <TH> Reason </TH> <TH> Details </TH> </TR> <TR> <TD>HealthcheckResult</TD> <TD>OK</TD> <TD>Path '/tmp/dead' was not found</TD> </TR> </TBODY> </TABLE> <HR></HR> <H2>1 greenthread(s) active:</H2> <TABLE bgcolor="#ffffff" border="1"> <TBODY> <TR> <TD><PRE> File "oslo_middleware/healthcheck/__main__.py", line 94, in <module> main() File "oslo_middleware/healthcheck/__main__.py", line 90, in main server.serve_forever() ... </PRE></TD> </TR> </TBODY> </TABLE> <HR></HR> <H2>1 thread(s) active:</H2> <TABLE bgcolor="#ffffff" border="1"> <TBODY> <TR> <TD><PRE> File "oslo_middleware/healthcheck/__main__.py", line 94, in <module> main() File "oslo_middleware/healthcheck/__main__.py", line 90, in main server.serve_forever() .... </TR> </TBODY> </TABLE> </BODY> </HTML>Example of paste configuration:
[app:healthcheck] use = egg:oslo.middleware:healthcheck backends = disable_by_file disable_by_file_path = /var/run/nova/healthcheck_disable [pipeline:public_api] pipeline = healthcheck sizelimit [...] public_service
Multiple filter sections can be defined if it desired to have pipelines with different healthcheck configuration, example:
[composite:public_api] use = egg:Paste#urlmap / = public_api_pipeline /healthcheck = healthcheck_public [composite:admin_api] use = egg:Paste#urlmap / = admin_api_pipeline /healthcheck = healthcheck_admin [pipeline:public_api_pipeline] pipeline = sizelimit [...] public_service [pipeline:admin_api_pipeline] pipeline = sizelimit [...] admin_service [app:healthcheck_public] use = egg:oslo.middleware:healthcheck backends = disable_by_file disable_by_file_path = /var/run/nova/healthcheck_public_disable [filter:healthcheck_admin] use = egg:oslo.middleware:healthcheck backends = disable_by_file disable_by_file_path = /var/run/nova/healthcheck_admin_disable
- classmethod app_factory(global_conf, **local_conf)¶
Factory method for paste.deploy.
- Parameters
global_conf – dict of options for all middlewares (usually the [DEFAULT] section of the paste deploy configuration file)
local_conf – options dedicated to this middleware (usually the option defined in the middleware section of the paste deploy configuration file)
- classmethod factory(global_conf, **local_conf)¶
Factory method for paste.deploy.
- Parameters
global_conf – dict of options for all middlewares (usually the [DEFAULT] section of the paste deploy configuration file)
local_conf – options dedicated to this middleware (usually the option defined in the middleware section of the paste deploy configuration file)
- class oslo_middleware.healthcheck.disable_by_file.DisableByFileHealthcheck(*args, **kwargs)¶
DisableByFile healthcheck middleware plugin
This plugin checks presence of a file to report if the service is unavailable or not.
Example of middleware configuration:
[filter:healthcheck] paste.filter_factory = oslo_middleware:Healthcheck.factory path = /healthcheck backends = disable_by_file disable_by_file_path = /var/run/nova/healthcheck_disable # set to True to enable detailed output, False is the default detailed = False
- healthcheck(server_port)¶
method called by the healthcheck middleware
return: HealthcheckResult object
- class oslo_middleware.healthcheck.disable_by_file.DisableByFilesPortsHealthcheck(*args, **kwargs)¶
DisableByFilesPorts healthcheck middleware plugin
This plugin checks presence of a file that is provided for a application running on a certain port to report if the service is unavailable or not.
Example of middleware configuration:
[filter:healthcheck] paste.filter_factory = oslo_middleware:Healthcheck.factory path = /healthcheck backends = disable_by_files_ports disable_by_file_paths = 5000:/var/run/keystone/healthcheck_disable, 35357:/var/run/keystone/admin_healthcheck_disable # set to True to enable detailed output, False is the default detailed = False
- healthcheck(server_port)¶
method called by the healthcheck middleware
return: HealthcheckResult object
Available Plugins¶
disable_by_file¶
DisableByFile healthcheck middleware plugin
This plugin checks presence of a file to report if the service is unavailable or not.
Example of middleware configuration:
[filter:healthcheck]
paste.filter_factory = oslo_middleware:Healthcheck.factory
path = /healthcheck
backends = disable_by_file
disable_by_file_path = /var/run/nova/healthcheck_disable
# set to True to enable detailed output, False is the default
detailed = False
disable_by_files_ports¶
DisableByFilesPorts healthcheck middleware plugin
This plugin checks presence of a file that is provided for a application running on a certain port to report if the service is unavailable or not.
Example of middleware configuration:
[filter:healthcheck]
paste.filter_factory = oslo_middleware:Healthcheck.factory
path = /healthcheck
backends = disable_by_files_ports
disable_by_file_paths = 5000:/var/run/keystone/healthcheck_disable, 35357:/var/run/keystone/admin_healthcheck_disable
# set to True to enable detailed output, False is the default
detailed = False
