supvisors 0.11

A Control System for Distributed Applications

Supvisors

Supvisors is a Control System for Distributed Applications, based on multiple instances of Supervisor running over multiple nodes.

The main features are:

• a new web-based dashboard that replaces the default dashboard of Supervisor,
• an extended XML-RPC API to control applications and multiple Supervisor instances,
• the definition of a rules file to handle:
  • the starting sequence of the applications,
  • the stopping sequence of the applications,
  • the starting strategy of the processes,
  • the strategy to apply when a process crashes.

Supervisor Enhancements

Supvisors proposes a contribution to the following Supervisor issues:

• #122 - supervisord Starts All Processes at the Same Time
• #177 - Dynamic numproc change
• #456 - Add the ability to set different "restart policies" on process workers
• #520 - allow a program to wait for another to stop before being stopped?
• #723 - Restart waits for all processes to stop before starting any
• #763 - unexpected exit not easy to read in status or getProcessInfo
• #874 - Bring down one process when other process gets killed in a group
• #1023 - Pass arguments to program when starting a job?
• #1150 - Why do event listeners not report the process exit status when stopped/crashed?

Supported Platforms

Supvisors has been tested and is known to run on Linux (CentOS 8.3). It will likely work fine on most UNIX systems.

Supvisors will not run at all under any version of Windows.

Supvisors >= 0.2 works with Python 3.6 or later.

Supvisors 0.1 (available on PyPi) works with Python 2.7 (and former versions of Supervisor, i.e. 3.3.0) but is not maintained anymore.

Dependencies

Supvisors has dependencies on:

|-----------------------------------------------|---------|----------|

Package	Release	Optional
Supervisor	4.2.4
PyZMQ	20.0.0
psutil	5.7.3	X
matplotlib	3.3.3	X
lxml	4.6.2	X
-----------------------------------------------	---------	----------

Please note that some of these dependencies may have their own dependencies.

Versions are given for information. Although Supvisors has been developed and tested with these releases, the minimal release of each dependency is unknown. Other releases are likely working as well.

Installation

Supvisors can be installed with pip install:

   # minimal install (including Supervisor and PyZMQ)
   [bash] > pip install supvisors

   # extra install for all optional dependencies
   [bash] > pip install supvisors[all]

Documentation

You can view the current Supvisors documentation here.

You will find detailed installation and configuration documentation.

Reporting Bugs and Viewing the Source Repository

Please report bugs in the Github issue tracker.

You can view the source repository for Supvisors.

Contributing

Not opened yet.

Change Log

0.11 (2022-01-02)

• Fixed Issue #99. Update the Supvisors design so that it can be used to supervise multiple Supervisor instances on multiple nodes. This update had a major impact on the source code. More particularly:

  • The XML-RPCs get_master_identifier, get_instance_info and get_all_instances_info have been added to replace get_master_address, get_address_info and get_all_addresses_info.
  • The supervisorctl command instance_status has been added to replace address_status.
  • The XML-RPCs that would return attributes address_name and addresses are now returning identifier and identifiers respectively. This impacts the following XML-RPCs (and related supervisorctl commands):
    • get_application_info
    • get_all_application_info
    • get_application_rules
    • get_address_info
    • get_all_addresses_info
    • get_all_process_info
    • get_process_info
    • get_process_rules
    • get_conflicts.
  • The supvisors_list option has been added to replace address_list in the Supvisors section of the Supervisor configuration file. This option accepts a more complex definition: <identifier>host_name:http_port:internal_port. Note that the simple host_name is still supported in the event where Supvisors doesn't have to deal with multiple Supervisor instances on the same node.
  • The core_identifiers option has been added to replace force_synchro_if in the Supvisors section of the Supervisor configuration file. It targets the names deduced from the supvisors_list option.
  • The identifiers option has been added to replace the addresses option in the Supvisors rules file. This option targets the names deduced from the supvisors_list option.
  • The address-like attributes, XML-RPCs and options are deprecated and will be removed in the next version.

• Fixed Issue #98. Move the heartbeat emission to the Supvisors thread to avoid being impacted by a Supervisor momentary freeze. On the heartbeat reception part, consider that the node is SILENT based on a number of ticks instead of time.

• Fix issue with supvisors.stop_process XML-RPC that wouldn't stop all processes when any of the targeted processes is already stopped.

• Fix exception when authorization is received from a node that is not in CHECKING state.

• Fix regression (missing disconnect) on node isolation when fencing is activated.

• Fix issue in statistics compiler when network interfaces are dynamically created / removed.

• Refactoring of Starter and Stopper.

• The module rpcrequests has been removed because useless. The function getRPCInterface of th module supervisor.childutils does the job.

• The startsecs and stopwaitsecs program options have been added to the results of get_all_local_process_info and get_local_process_info.

• The option rules_file is updated to rules_files and supports multiple files for Supvisors rules. The option rules_file is thus deprecated and will be removed in the next version.

• Add a new restart_sequence XML-RPC to trigger a full application start sequence.

• Update the restart_application and restart_process XML-RPC so that processes can restart themselves using them.

• Add expected_exit to the output of supervisorctl sstatus when the process is EXITED.

• Add the new option stats_enabled to enable/disable the statistics function.

• Update start_process, stop_process, restart_process, process_rules in supervisorctl so that calls are made on each individually process rather than process group when all is used as parameter.

• Add exit codes to erroneous Supvisors calls in supervisorctl.

• When aborting jobs when re-entering the INITIALIZATION state, clear the structure holding the jobs in progress. It has been found to stick Supvisors in the DEPLOYMENT state in the event where the Master node is temporarily SILENT.

• Restrict the use of the XML-RPCs start_application, stop_application, restart_application to Managed applications only.

• Review the logic of the refresh button in the Web UI.

• Add node time to the node boxes in the Main page of the Web UI.

• Sort alphabetically the entries of the application menu of the Web UI.

• Update the mouse pointer look on nodes in the Main and Host pages of the Web UI.

• Remove the useless timecode in the header of the Process and Host pages of the Web UI as it is now provided at the bottom right of all pages.

• Add class "action" to Web UI buttons that trigger an XML-RPC.

• Switch from Travis-CI to GitHub Actions for continuous integration.

0.10 (2021-09-05)

• Implement Supervisor Issue #177. It is possible to update dynamically the program numprocs using the new update_numprocs XML-RPC.

• Add targets Python 3.7 and Python 3.8 to Travis-CI.

0.9 (2021-08-31)

• Enable the hash '#' for the addresses of a non-distributed application.

• Add supvisorsctl to pally the lack of support of supervisorctl when used with --serverurl URL option. See related Supervisor Issue #1455.

• Provide breed.py as a binary of Supvisors: supvisors_breed. The script only considers group duplication as it is fully valid to include multiple times a program definition in several groups.

• Move the contents of the [supvisors] section into the [rpcinterface:supvisors] section and benefit from the configuration structure provided by Supervisor. The [supvisors] section itself is thus obsolete.

• Remove deprecated support of pattern elements.

• Fixed issue when using the Web UI Application page from a previous launch.

• Invert the stop sequence logic, starting from the greatest stop_sequence number to the lowest one.

• When stop_sequence is not set in the rules files, it is defaulted to the start_sequence value. With the new stop sequence logic, the stop sequence is by default exactly the opposite of the start sequence.

• Fixed Nodes' column width for supervisorctl application_rules.

• CHANGES.rst replaced with CHANGES.md.

• 'Scenario 3' has been added to the Supvisors use cases.

• A 'Gathering' configuration has been added to the Supvisors use cases. It combines all uses cases.

0.8 (2021-08-22)

• Fixed exception in INITIALIZATION state when the Master declared by other nodes is not RUNNING yet and the core nodes are RUNNING.

• Fixed exception when program rules and extra arguments are tested against a program unknown to the local Supervisor.

• Fixed issue about program patterns that were applicable to all elements. The scope of program patterns is now limited to their owner application.

• Fixed issue with infinite tries of application restart when the process cannot be started due to a lack of resources and RESTART_APPLICATION is set on the program in the Supvisors rules file.

• Fixed issue about application state not updated after a node has become silent.

• Fixed issue when choosing a node in Starter. Apply the requests that have not been satisfied yet for non-distributed applications.

• Logic for application major / minor failures reviewed.

• Simplify the insertion of applications to start or stop in Commander jobs.

• In the rules file, support for application patterns has been added.

• In the rules file, pattern elements are deprecated and are replaced by program elements with a pattern attribute instead of a name attribute. Support for pattern elements will be removed in the next version of Supvisors.

• Node aliases have been added to the rules file.

• Add the current node to all pages of Web UI to be aware of the node that displays the page.

• The Web UI is updated to handle a large list of applications, nodes, processor cores and network interfaces.

• In the Process page of the Web UI, expand / shrink actions are not applicable to programs that are not owned by a Supervisor group.

• In the application navigation menu of the Web UI, add a red light near the Applications title if any application has raised a failure.

• In the Application page of the Web UI, default starting strategy is the starting strategy defined in the rules file for the application considered.

• In the Application ang Process page, the detailed process statistics can be deselected.

• Titles added to the output of :program:supervisorctl address_status and application_info.

• The XML schema has been moved to a separate file rules.xsd.

• Remove dependency to netifaces as psutil provides the function.

• 'Scenario 2' has been added to the Supvisors use cases.

• A script breed.py has been added to the installation package. It can be used to duplicate the applications based on a template configuration and more particularly used to prepare the Scenario 2 of the Supvisors use cases.

0.7 (2021-08-15)

• Fixed Issue #92. The Master drives the state of all Supvisors instances and a simplified state machine has been assigned to non-master Supvisors instances. The loss of the Master instance is managed in all relevant states.

• Fixed issue about applications that would be started automatically whereas their start_sequence is 0. The regression has been introduced during the implementation of applications repair in Supvisors 0.6.

• Enable stop sequence on Unmanaged applications.

• In the application navigation menu of the Web UI, add a red light to applications having raised a failure.

• New application rules distributed and addresses added to the Supvisors rules file. Non-distributed applications have all their processes started on the same node chosen in accordance with the addresses and the starting_strategy.

• Starting strategy added to the application rules.

• Fixed issue when choosing a node in Starter. The starting strategies considers the current load of the nodes and includes the requests that have not been satisfied yet.

• Fixed issue with infinite process restart when the process crashes and RESTART_PROCESS is set on the program in the Supvisors rules file. When the process crashes, only the Supervisor autorestart applies. The Supvisors RESTART_PROCESS applies only when the node becomes inactive.

• Fixed exception when forcing the state on a process that is unknown to the local Supervisor.

• Promote the RESTART_PROCESS into RESTART_APPLICATION if the application is stopped.

• For the Master election, give a priority to nodes declared in the forced_synchro_if option if used.

• When using the forced_synchro_if option and when auto_fence is activated, do not isolate nodes as long as synchro_timeout has not passed.

• In the INITALIZATION state, skip the synchronization phase upon notification of a known Master and adopt it.

• Add reciprocity to isolation even if auto_fence is not activated.

• In the process description of the Web UI Application page, add information about the node name. In particular, it is useful to know where the process was running when it is stopped.

• Start adding use cases to documentation, inspired by real examples. 'Scenario 1' has been added.

0.6 (2021-08-01)

• Applications that are not declared in the rules file are not managed. Unmanaged applications have no start/stop sequence, no state and status (always STOPPED) and Supvisors does not raise a conflict if multiple instances are running over multiple nodes.

• Improve Supvisors stability when dealing with remote programs undefined locally.

• Add expand / shrink actions to applications to the ProcInstanceView of the Web UI.

• Upon authorization of a new node in Supvisors, back to DEPLOYMENT state to repair applications.

• Add RPC change_log_level to dynamically change the Supvisors logger level.

• Application state is evaluated only against the starting sequence of its processes.

• Fixed blocking issue when Master is stopped while in DEPLOYMENT state.

• Fixed issue with applications that would not fully stop when using the STOP_APPLICATION starting failure strategy.

• Fixed issue related to Issue #85. An exception was raised when the program procnum was greater than the list of applicable nodes.

• Fixed Issue #91. Fix CSS style on the process tables in HTML.

• Fixed Issue #90. The Supvisors Master node drives the transition to OPERATION.

• In the Web UI, set the process state color to FATAL when the process has exited unexpectedly.

• Change the default expected loading to 0 in the program rules.

• Python Enum used for enumerations (not available in Python 2.7).

• Remove supvisors_shortcuts from source code to get rid of IDE warnings.

• All unit tests updated from unittest to pytest.

• Include this Change Log to documentation.

0.5 (2021-03-01)

• New option force_synchro_if to force the end of the synchronization phase when a subset of nodes is active.

• New starting strategy LOCAL added to command the starting of an application on the local node only.

• Fixed Issue #87. Under particular circumstances, Supvisors could have multiple Master nodes.

• Fixed Issue #86. The starting and stopping sequences may fail and block when a sub-sequence includes only failed programs.

• Fixed Issue #85. When using # in the address_list program rule of the Supvisors rules file, a subset of nodes can optionally be defined.

• Fixed Issue #84. In the Supvisors rules file, program rules can be defined using both model reference and attributes.

• The Web UI uses the default starting strategy of the configuration file.

• The layout of Web UI statistics sections has been rearranged.

• Fixed CSS style missing for CHECKING node state in tables.

• Star added to the node box of the Master instance on the main page.

• Type annotations are added progressively in source code.

• Start switching from unittest to pytest.

• Logs (especially debug and trace) updated to remove printed objects.

0.4 (2021-02-14)

• Auto-refresh button added to all pages.

• Web UI Main page reworked by adding a subdivision of application in node boxes.

• Fixed exception when exiting using Ctrl+c from shell.

• Fixed exception when rules files is not provided.

0.3 (2020-12-29)

• Fixed Issue #81. When Supvisors logfile is set to AUTO, Supvisors uses the same logger as Supervisor.

• Fixed Issue #79. When FATAL or UNKNOWN Process state is forced by Supvisors, spawnerr was missing in the listener payload.

• Useless folder rsc_ref deleted.

• design folder moved to a dedicated GitHub repository.

• 100% coverage reached in unit tests.

0.2 (2020-12-14)

• Migration to Python 3.6. Versions of dependencies are refreshed, more particularly Supervisor 4.2.1.

• CSS of Web UI updated / simplified.

• New action added to Host Process page of WebUI: tail -f stderr button.

• New information actions added to Application page of WebUI:

  • description field.
  • clear logs, tail -f stdout, tail -f stderr buttons.

• Fixed Issue #75. Supvisors takes into account the username and the password of inet_http_server in the supervisord section.

• Fixed Issue #17. The user selections on the web UI are passed to the URL.

• Fixed Issue #72. The extra arguments are shared between all Supvisors instances.

• README.rst replaced with README.md.

• Coverage improved in tests.

• Docs target added to Travis-CI.

0.1 (2017-08-11)

Initial release.