b38f72b212
Currently at least 1 rpc worker is launched even when a user requests
zero workers by setting rpc_workers=0. The setting of rpc_workers=0 is
used when ml2-ovn plugin is used without any additional agent, and in
this deployment pattern the single rpc worker is not at all used.
This change ensures no rpc worker is launched when rpc_workers options
is explicitly set to 0. This may be classified as a breaking change,
but is consistent with the earlier change[1] for rpc_workers=0.
[1] 3e1e2d63b3
Closes-Bug: #2052484
Change-Id: I878e50c3192ecd3b145ded0ab8394845a089696e
163 lines
4.7 KiB
ReStructuredText
163 lines
4.7 KiB
ReStructuredText
.. _config-wsgi:
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WSGI Usage with the Neutron API
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===============================
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This document is a guide to deploying Neutron using WSGI. There are two ways to
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deploy using WSGI: ``uwsgi`` and Apache ``mod_wsgi``.
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Please note that if you intend to use mode uwsgi, you should install the
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``mode_proxy_uwsgi`` module. For example on deb-based system:
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.. code-block:: console
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# sudo apt-get install libapache2-mod-proxy-uwsgi
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# sudo a2enmod proxy
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# sudo a2enmod proxy_uwsgi
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.. end
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WSGI Application
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----------------
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The function ``neutron.server.get_application`` will setup a WSGI application
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to run behind uwsgi and mod_wsgi.
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Neutron API behind uwsgi
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------------------------
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Create a ``/etc/neutron/neutron-api-uwsgi.ini`` file with the content below:
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.. code-block:: ini
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[uwsgi]
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chmod-socket = 666
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socket = /var/run/uwsgi/neutron-api.socket
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lazy-apps = true
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add-header = Connection: close
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buffer-size = 65535
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hook-master-start = unix_signal:15 gracefully_kill_them_all
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thunder-lock = true
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plugins = python
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enable-threads = true
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worker-reload-mercy = 90
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exit-on-reload = false
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die-on-term = true
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master = true
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processes = 2
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wsgi-file = <path-to-neutron-bin-dir>/neutron-api
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.. end
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Start neutron-api:
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.. code-block:: console
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# uwsgi --procname-prefix neutron-api --ini /etc/neutron/neutron-api-uwsgi.ini
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.. end
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Neutron API behind mod_wsgi
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---------------------------
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Create ``/etc/apache2/neutron.conf`` with content below:
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.. code-block:: ini
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Listen 9696
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LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\" %D(us)" neutron_combined
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<Directory /usr/local/bin>
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Require all granted
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</Directory>
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<VirtualHost *:9696>
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WSGIDaemonProcess neutron-server processes=1 threads=1 user=stack display-name=%{GROUP}
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WSGIProcessGroup neutron-server
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WSGIScriptAlias / <path-to-neutron-bin-dir>/neutron-api
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WSGIApplicationGroup %{GLOBAL}
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WSGIPassAuthorization On
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ErrorLogFormat "%M"
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ErrorLog /var/log/neutron/neutron.log
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CustomLog /var/log/neutron/neutron_access.log neutron_combined
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</VirtualHost>
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Alias /networking <path-to-neutron-bin-dir>/neutron-api
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<Location /networking>
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SetHandler wsgi-script
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Options +ExecCGI
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WSGIProcessGroup neutron-server
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WSGIApplicationGroup %{GLOBAL}
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WSGIPassAuthorization On
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</Location>
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WSGISocketPrefix /var/run/apache2
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.. end
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For deb-based systems copy or symlink the file to ``/etc/apache2/sites-available``.
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Then enable the neutron site:
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.. code-block:: console
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# a2ensite neutron
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# systemctl reload apache2.service
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.. end
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For rpm-based systems copy the file to ``/etc/httpd/conf.d``. Then enable the
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neutron site:
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.. code-block:: console
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# systemctl reload httpd.service
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.. end
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Start Neutron RPC server
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------------------------
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When Neutron API is served by a web server (like Apache2) it is difficult
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to start an rpc listener thread. So start the Neutron RPC server process to
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serve this job:
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.. code-block:: console
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# /usr/bin/neutron-rpc-server --config-file /etc/neutron/neutron.conf --config-file /etc/neutron/plugins/ml2/ml2_conf.ini
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.. end
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Neutron Worker Processes
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------------------------
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Neutron will attempt to spawn a number of child processes for handling API
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and RPC requests. The number of API workers is set to the number of CPU
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cores, further limited by available memory, and the number of RPC workers
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is set to half that number.
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It is strongly recommended that all deployers set these values themselves,
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via the api_workers and rpc_workers configuration parameters.
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For a cloud with a high load to a relatively small number of objects,
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a smaller value for api_workers will provide better performance than
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many (somewhere around 4-8.) For a cloud with a high load to lots of
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different objects, then the more the better. Budget neutron-server
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using about 2GB of RAM in steady-state.
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For rpc_workers, there needs to be enough to keep up with incoming
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events from the various neutron agents. Signs that there are too few
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can be agent heartbeats arriving late, nova vif bindings timing out
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on the hypervisors, or rpc message timeout exceptions in agent logs
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(for example, "broken pipe" errors).
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There is also the rpc_state_report_workers option, which determines
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the number fo RPC worker processes dedicated to process state reports
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from the various agents. This may be increased to resolve frequent delay
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in processing agents heartbeats.
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.. note::
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If OVN ML2 plugin is used without any additional agents, neutron requires
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no worker for RPC message processing. Set both rpc_workers and
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rpc_state_report_workers to 0, to disable RPC workers.
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