=============================== Troubleshooting the Salt Master =============================== Running in the Foreground ========================= A great deal of information is available via the debug logging system, if you are having issues with minions connecting or not starting run the master in the foreground: .. code-block:: bash # salt-master -l debug Anyone wanting to run Salt daemons via a process supervisor such as `monit`_, `runit`_, or `supervisord`_, should omit the ``-d`` argument to the daemons and run them in the foreground. .. _`monit`: http://mmonit.com/monit/ .. _`runit`: http://smarden.org/runit/ .. _`supervisord`: http://supervisord.org/ What Ports does the Master Need Open? ===================================== For the master, TCP ports 4505 and 4506 need to be open. If you've put both your Salt master and minion in debug mode and don't see an acknowledgment that your minion has connected, it could very well be a firewall interfering with the connection. See our :doc:`firewall configuration ` page for help opening the firewall on various platforms. If you've opened the correct TCP ports and still aren't seeing connections, check that no additional access control system such as `SELinux`_ or `AppArmor`_ is blocking Salt. .. _`SELinux`: https://en.wikipedia.org/wiki/Security-Enhanced_Linux .. _`AppArmor`: http://wiki.apparmor.net/index.php/Main_Page Too many open files =================== The salt-master needs at least 2 sockets per host that connects to it, one for the Publisher and one for response port. Thus, large installations may, upon scaling up the number of minions accessing a given master, encounter: .. code-block:: bash 12:45:29,289 [salt.master ][INFO ] Starting Salt worker process 38 Too many open files sock != -1 (tcp_listener.cpp:335) The solution to this would be to check the number of files allowed to be opened by the user running salt-master (root by default): .. code-block:: bash [root@salt-master ~]# ulimit -n 1024 If this value is not equal to at least twice the number of minions, then it will need to be raised. For example, in an environment with 1800 minions, the ``nofile`` limit should be set to no less than 3600. This can be done by creating the file ``/etc/security/limits.d/99-salt.conf``, with the following contents:: root hard nofile 4096 root soft nofile 4096 Replace ``root`` with the user under which the master runs, if different. If your master does not have an ``/etc/security/limits.d`` directory, the lines can simply be appended to ``/etc/security/limits.conf``. As with any change to resource limits, it is best to stay logged into your current shell and open another shell to run ``ulimit -n`` again and verify that the changes were applied correctly. Additionally, if your master is running upstart, it may be necessary to specify the ``nofile`` limit in ``/etc/default/salt-master`` if upstart isn't respecting your resource limits: .. code-block:: text limit nofile 4096 4096 .. note:: The above is simply an example of how to set these values, and you may wish to increase them even further if your Salt master is doing more than just running Salt. Salt Master Stops Responding ============================ There are known bugs with ZeroMQ versions less than 2.1.11 which can cause the Salt master to not respond properly. If you're running a ZeroMQ version greater than or equal to 2.1.9, you can work around the bug by setting the sysctls ``net.core.rmem_max`` and ``net.core.wmem_max`` to 16777216. Next, set the third field in ``net.ipv4.tcp_rmem`` and ``net.ipv4.tcp_wmem`` to at least 16777216. You can do it manually with something like: .. code-block:: bash # echo 16777216 > /proc/sys/net/core/rmem_max # echo 16777216 > /proc/sys/net/core/wmem_max # echo "4096 87380 16777216" > /proc/sys/net/ipv4/tcp_rmem # echo "4096 87380 16777216" > /proc/sys/net/ipv4/tcp_wmem Or with the following Salt state: .. code-block:: yaml :linenos: net.core.rmem_max: sysctl: - present - value: 16777216 net.core.wmem_max: sysctl: - present - value: 16777216 net.ipv4.tcp_rmem: sysctl: - present - value: 4096 87380 16777216 net.ipv4.tcp_wmem: sysctl: - present - value: 4096 87380 16777216 Live Python Debug Output ======================== If the master seems to be unresponsive, a SIGUSR1 can be passed to the salt-master threads to display what piece of code is executing. This debug information can be invaluable in tracking down bugs. To pass a SIGUSR1 to the master, first make sure the minion is running in the foreground. Stop the service if it is running as a daemon, and start it in the foreground like so: .. code-block:: bash # salt-master -l debug Then pass the signal to the master when it seems to be unresponsive: .. code-block:: bash # killall -SIGUSR1 salt-master When filing an issue or sending questions to the mailing list for a problem with an unresponsive daemon, be sure to include this information if possible. Live Salt-Master Profiling ========================== When faced with performance problems one can turn on master process profiling by sending it SIGUSR2. .. code-block:: bash # killall -SIGUSR2 salt-master This will activate ``yappi`` profiler inside salt-master code, then after some time one must send SIGUSR2 again to stop profiling and save results to file. If run in foreground salt-master will report filename for the results, which are usually located under ``/tmp`` on Unix-based OSes and ``c:\temp`` on windows. Results can then be analyzed with `kcachegrind`_ or similar tool. .. _`kcachegrind`: http://kcachegrind.sourceforge.net/html/Home.html Commands Time Out or Do Not Return Output ========================================= Depending on your OS (this is most common on Ubuntu due to apt-get) you may sometimes encounter times where your highstate, or other long running commands do not return output. .. note:: A number of timing issues were resolved in the 2014.1 release of Salt. Upgrading to at least this version is strongly recommended if timeouts persist. By default the timeout is set to 5 seconds. The timeout value can easily be increased by modifying the ``timeout`` line within your ``/etc/salt/master`` configuration file. Passing the -c Option to Salt Returns a Permissions Error ========================================================= Using the ``-c`` option with the Salt command modifies the configuration directory. When the configuration file is read it will still base data off of the ``root_dir`` setting. This can result in unintended behavior if you are expecting files such as ``/etc/salt/pki`` to be pulled from the location specified with ``-c``. Modify the ``root_dir`` setting to address this behavior. Salt Master Auth Flooding ========================= In large installations, care must be taken not to overwhealm the master with authentication requests. Several options can be set on the master which mitigate the chances of an authentication flood from causing an interuption in service. .. note:: recon_default: The average number of seconds to wait between reconnection attempts. recon_max: The maximum number of seconds to wait between reconnection attempts. recon_randomize: A flag to indicate whether the recon_default value should be randomized. acceptance_wait_time: The number of seconds to wait for a reply to each authentication request. random_reauth_delay: The range of seconds across which the minions should attempt to randomize authentication attempts. auth_timeout: The total time to wait for the authentication process to complete, regardless of the number of attempts.