Sigterm

Hello everyone,I’m trying to understand the behavior of idle timeout and graceful shutdown in Azure App Service when running on Linux. I have a .NET (or any other default template) app deployed on Azure App Service using a Linux container. Here’s a summary of my observations and questions: Expected Behavior on Windows vs. Linux:– On Windows App Service, when “Always On” is disabled, the platform automatically unloads an idle app (typically after around 20 minutes of inactivity). This auto-unload triggers a graceful shutdown signal (SIGTERM) to the application, allowing it to complete cleanup tasks.– In contrast, my tests on Linux (using the default template code) show that the container continues running indefinitely—even with “Always On” off—and no SIGTERM is received due to inactivity. SIGTERM for Graceful Shutdown:– I understand that Linux containers do support receiving SIGTERM for graceful shutdown when the container is actually stopped (for example, during a scale-down, redeployment, or manual stop). I have implemented signal handlers in my application to catch SIGTERM for cleanup. However, in the idle scenario (with no incoming traffic), the app never receives SIGTERM; it just keeps running. – I came across a discussion (e.g., via DeepSeek R1) suggesting that idle shutdown might be supported via SIGTERM on Linux. Yet, I couldn’t find any official documentation that confirms an idle timeout mechanism (like on Windows) for Linux App Service. My Testing Details:– I deployed a new app (using the default .NET template) to an Azure App Service on Linux.– I disabled “Always On” in the portal expecting, based on Windows behavior, that after a period of inactivity (around 20 minutes) the container might be unloaded and receive a SIGTERM for graceful shutdown.– Instead, the container remained active and no SIGTERM (or any shutdown signal) was triggered by inactivity. – I have searched through

It a so-called signal, called SIGTERM. Which is a way to tell a process:Hey, can you please close yourself, normally? Save your data, do whatever you need to do, and then exit.💡Note: sudo kill 778 would have also worked, and had the same effect. Since, by default, the kill command sends the SIGTERM signal anyway. But I prefer to use the specific options (-s SIGTERM) for commands that could be disruptive. Because, what if the default changes in the future, for some reason? And instead of a graceful terminate signal I accidentally send a force kill signal?No error output means that the SIGTERM signal was sent. But just because a signal is sent does not mean that the application acted on it. A signal is a request, that an application can fulfill, or not.So we should check if the process with PID 778 was closed, by running:ps 778If it looks like this, with no content under the PID, STAT, COMMAND columns, then the process was closed:Essentially, SIGTERM is a "nice" signal. It just politely asks the process to close itself. And it's up to the process to also be polite, and listen to the request.Which means, if the application is stuck in some way, then it might ignore SIGTERM, and not close itself. So it's time to bring out the big guns: The SIGKILL signal!Method 2 – Forcefully Terminate the Process with SIGKILLSIGKILL should only be used as a last resort. When there's just no other way to close that process. Why?Because SIGTERM allows the application to save its data and close normally.But SIGKILL is brutal. It instantly kills the process, without allowing it to save data, or wrap up whatever it was doing. Which brings a small chance of data corruption, or rather, incomplete data, if the process was working on something and it was killed in the middle of that.Think of SIGTERM as normally shutting down your computer. And SIGKILL as pulling the power cable (and battery) from your computer, or pressing the reset button. Of course, the "computer" in this case is the process we're working with.Either

Error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.jun 24 21:44:58 Q systemd-resolved[981]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.jun 24 21:49:58 Q systemd-resolved[981]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.jun 24 21:54:31 Q systemd[1]: poweroff.target: Job poweroff.target/start timed out.jun 24 21:54:31 Q systemd[1]: Timed out starting Power-Off.jun 24 21:54:31 Q systemd[1]: poweroff.target: Job poweroff.target/start failed with result 'timeout'.jun 24 21:54:31 Q systemd[1]: Forcibly powering off: job timed outjun 24 21:54:31 Q systemd-logind[1062]: Operation 'shutdown' finished.jun 24 21:54:31 Q systemd[1]: Shutting down.jun 24 21:54:31 Q systemd-shutdown[1]: Syncing filesystems and block devices.jun 24 21:54:31 Q systemd-shutdown[1]: Sending SIGTERM to remaining processes...jun 24 21:54:31 Q dnsmasq[1412]: exiting on receipt of SIGTERMjun 24 21:54:31 Q NetworkManager[1027]: [1593028471.8127] caught SIGTERM, shutting down normally.jun 24 21:54:31 Q systemd-journald[456]: Journal stoppedrunningdmidecode -s bios-versionreturns F42aI have an aorus x470 ultra gaming cfamd ryzen 3700xrtx 2070

Bundled Katana USD plug-ins). SeeBuilding Katana USD Plug-ins.KATANA_USD_PLUGINS_DISABLEDDisables the startup environment setup for the KatanaUsdPlugins shipped withKatana by default. This will be required to set to 1 if you would liketo use your own KatanaUsdPlugins, as two sets of Plugins cannot be usedat the same time.Python Search Path¶Katana’s search paths for Python module files are built from different parts:KATANA_DEBUG_PRE_PYTHONPATH (user-defined)Katana’s own default search paths.PYTHONPATH (user-defined) andsite-specific configurationvia sitecustomize.py (user-defined)KATANA_POST_PYTHONPATH (user-defined)Each of these parts is a list of filesystem paths, separated by the OS-specificpath separator (colon : on Linux, semicolon ; on Windows).The combined Python search paths are made available in theKATANA_INTERNAL_PYTHONPATH environment variable that is set by Katana.That variable is used to override the paths for the Python interpreter insideof renderboot when renderboot is started, after the Python interpreteris initialized.Note that sys.path may contain additional paths as a result ofplug-in startup scripts.NoteThe Katana Queue Daemon (KQD) script and the Agent scripts that itspawns are run in a Python interpreter that is initialized viaPYTHONPATH, in addition to the following paths:$KATANA_ROOT/plugins/Resources/Core/Plugins/ – so that KQD canimport the kq Python package of Katana Queue$KATANA_ROOT/bin/python/ – so that KQD can import the zmqthird-party Python packageCautionKATANA_DEBUG_PRE_PYTHONPATH is meant to be used for debugging purposesonly, as it may lead to unexpected application behavior due tonon-supported modules loaded in place of the application’s ones.Rendering¶DEFAULT_RENDER_TERMINATION_SIGNALOn Linux, Katana uses signals to terminate the renderboot process. When arender is canceled, the module responsible for starting renderboot firstchecks for a specific environment variable, to determine which signal shouldbe used.Katana currently supports renderer-specific variables that are named name>_RENDER_TERMINATION_SIGNAL, for example,ARNOLD_RENDER_TERMINATION_SIGNAL.Valid values for the variables are: SIGABRT, SIGKILL, SIGTERM. Ifno variable is set, the signal defaults to SIGTERM. The module then useskill(pid, signal) to terminate renderboot.ARNOLD_RENDER_TERMINATION_SIGNALSee DEFAULT_RENDER_TERMINATION_SIGNAL. By default, during applicationstartup, ARNOLD_RENDER_TERMINATION_SIGNAL is initialised to SIGKILL.PRMAN_RENDER_TERMINATION_SIGNALSee DEFAULT_RENDER_TERMINATION_SIGNAL.KATANA_CANCELLED_RENDER_PROCESS_GRACE_PERIOD ✨ New in Katana 4.0v4The time (in seconds) that a cancelled render process is allowed to continuerunning before Katana terminates it definitively. Default is 60 seconds.This environment variable is most relevant when the default SIGTERM signalis used in DEFAULT_RENDER_TERMINATION_SIGNAL, since sending that signal tothe process does not necessarily guarantee that the render process willterminate in a timely manner.DEFAULT_RENDERERDefault renderer. If not set, defaults to dl, the 3Delight renderer.KATANA_RENDER_TILE_SIZEGlobal tile size to be used in the render system 2D. The variable is a scalartype used both for the width and height of the tile.KATANA_RENDER_LOGFILEPath where render log should be saved.KATANA_CATALOG_REFRESH_RATERate at which Katana’s Catalog subsystem will trigger

Through the platform RightLink 10 receives a 'decommission for reboot' message, which is handled differently on Linux and Windows:Linux: it initiates an OS reboot (e.g., by changing to runlevel 6 on Linux) which sends a SIGTERM to the rightlink process. The Rightlink process then proceeds to run the decommission bundle if it has reached the 'operational' or 'stranded' state, which happens at the end of the boot bundle. Because of this, decommission scripts have a limited amount of time to run determined by the OS init system. This is set to 3 minutes on Linux though may be modified by changing the timeouts in the service config files for upstart/systemd. If setting the timeout for longer than 50 minutes, see Terminate and Stop-Start sections below.Windows: it runs the decommission bundle first, then initiates an OS reboot. This is because Windows has limited dependency management of services during shutdown, and very limited time to stop services. Because of this, RightLink will only execute decommission scripts for Windows if the reboot/terminate/stop was initiated via the RightScale API or dashboard and not if it was executed via the cloud console or on the machine. There is no timeout on the running of the decommission bundle in the RightLink code. However, see below for timeouts that apply to stop and terminate.When the OS starts the shutdown process it sends a kill SIGTERM signal to RightLink 10. For Linux, RightLink 10 fetches and executes the decommission bundle if it has achieved an 'operational' or 'stranded'

11:58:19 [error] 30909#0: *25441 connect() failed (111: Connection refused) while connecting to upstream, client: 81.57.19.196, server: cloud.2rock.fr, request: "PROPFIND /remote.php/webdav/Shared HTTP/1.1", upstream: " host: "cloud.2rock.fr"2016/10/15 11:58:21 [error] 30909#0: *25441 connect() failed (111: Connection refused) while connecting to upstream, client: 81.57.19.196, server: cloud.2rock.fr, request: "PROPFIND /remote.php/webdav/ HTTP/1.1", upstream: " host: "cloud.2rock.fr"2016/10/15 11:58:24 [error] 30909#0: *25441 connect() failed (111: Connection refused) while connecting to upstream, client: 81.57.19.196, server: cloud.2rock.fr, request: "PROPFIND /remote.php/webdav/Music HTTP/1.1", upstream: " host: "cloud.2rock.fr"2016/10/15 11:58:41 [error] 30909#0: *25441 connect() failed (111: Connection refused) while connecting to upstream, client: 81.57.19.196, server: cloud.2rock.fr, request: "PROPFIND /remote.php/webdav/ HTTP/1.1", upstream: " host: "cloud.2rock.fr"2016/10/15 11:58:44 [error] 30909#0: *25732 connect() failed (111: Connection refused) while connecting to upstream, client: 81.57.19.196, server: cloud.2rock.fr, request: "PROPFIND /remote.php/webdav/Documents HTTP/1.1", upstream: " host: "cloud.2rock.fr"2016/10/15 11:58:46 [error] 30909#0: *25732 connect() failed (111: Connection refused) while connecting to upstream, client: 81.57.19.196, server: cloud.2rock.fr, request: "PROPFIND /remote.php/webdav/ HTTP/1.1", upstream: " host: "cloud.2rock.fr"Apache (webserver with owncloud) error.logget('ae498358ce05d8c...')\n#1 /var/www/owncloud/lib/autoloader.php(145): OC\\Memcache\\Redis->get('OC_User')\n#2 [internal function]: OC\\Autoloader->load('OC_User')\n#3 /var/www/owncloud/lib/private/Log/Owncloud.php(97): spl_autoload_call('OC_User')\n#4 [internal function]: OC\\Log\\Owncloud::write('PHP', 'RedisException:...', 3)\n#5 /var/www/owncloud/lib/private/Log.php(294): call_user_func(Array, 'PHP', 'RedisException:...', 3)\n#6 /var/www/owncloud/lib/private/Log.php(152): OC\\Log->log(3, 'RedisException:...', Array)\n#7 /var/www/owncloud/lib/private/Log/ErrorHandler.php(80): OC\\Log->critical('RedisException:...', Array)\n#8 [internal function]: OC\\Log\\ErrorHandler->onException(Object(RedisException))\n#9 {main}\n thrown in /var/www/owncloud/lib/private/Memcache/Redis.php on line 51, referer: Oct 15 11:58:05.640958 2016] [:error] [pid 1492] [client 192.168.1.2:38831] PHP Fatal error: Uncaught exception 'RedisException' with message 'Redis server went away' in /var/www/owncloud/lib/private/Memcache/Redis.php:51\nStack trace:\n#0 /var/www/owncloud/lib/private/Memcache/Redis.php(51): Redis->get('ae498358ce05d8c...')\n#1 /var/www/owncloud/lib/autoloader.php(145): OC\\Memcache\\Redis->get('OC_User')\n#2 [internal function]: OC\\Autoloader->load('OC_User')\n#3 /var/www/owncloud/lib/private/Log/Owncloud.php(97): spl_autoload_call('OC_User')\n#4 [internal function]: OC\\Log\\Owncloud::write('PHP', 'Uncaught except...', 3)\n#5 /var/www/owncloud/lib/private/Log.php(294): call_user_func(Array, 'PHP', 'Uncaught except...', 3)\n#6 /var/www/owncloud/lib/private/Log.php(152): OC\\Log->log(3, 'Uncaught except...', Array)\n#7 /var/www/owncloud/lib/private/Log/ErrorHandler.php(67): OC\\Log->critical('Uncaught except...', Array)\n#8 [internal function]: OC\\Log\\ErrorHandler->onShutdown()\n#9 {main}\n thrown in /var/www/owncloud/lib/private/Memcache/Redis.php on line 51, referer: Oct 15 11:58:06.783816 2016] [mpm_prefork:notice] [pid 1488] AH00169: caught SIGTERM, shutting down[Sat Oct 15 11:58:50.747130 2016] [mpm_prefork:notice] [pid 506] AH00163: Apache/2.4.10 (Debian) OpenSSL/1.0.1t configured -- resuming normal operations[Sat Oct 15 11:58:50.939842 2016] [core:notice] [pid 506] AH00094: Command line: '/usr/sbin/apache2'[Sat Oct 15 12:29:08.521418 2016] [mpm_prefork:notice] [pid 506] AH00169: caught SIGTERM, shutting down[Sat Oct 15 12:29:11.431631 2016] [mpm_prefork:notice] [pid 3567] AH00163: Apache/2.4.10 (Debian) OpenSSL/1.0.1t configured -- resuming normal operations[Sat Oct 15 12:29:11.431686 2016] [core:notice] [pid 3567] AH00094: Command line: '/usr/sbin/apache2'">[Sat Oct 15 11:46:22.602171 2016] [mpm_prefork:notice] [pid 584] AH00163: Apache/2.4.10 (Debian) OpenSSL/1.0.1t configured -- resuming normal operations[Sat Oct 15 11:46:22.602204 2016] [core:notice] [pid 584] AH00094: Command line: '/usr/sbin/apache2'[Sat Oct 15 11:54:03.907965 2016] [mpm_prefork:notice] [pid 584] AH00169: caught SIGTERM, shutting down[Sat Oct 15 11:54:05.852502 2016] [mpm_prefork:notice] [pid 1340] AH00163: Apache/2.4.10 (Debian) OpenSSL/1.0.1t configured -- resuming normal operations[Sat Oct 15 11:54:05.852539 2016] [core:notice] [pid 1340] AH00094: Command line: '/usr/sbin/apache2'[Sat Oct 15 11:54:35.430150 2016] [mpm_prefork:notice] [pid 1340] AH00169: caught SIGTERM, shutting down[Sat Oct 15 11:55:31.331748 2016] [mpm_prefork:notice] [pid 1488] AH00163: Apache/2.4.10 (Debian) OpenSSL/1.0.1t configured -- resuming normal operations[Sat Oct 15 11:55:31.331808 2016] [core:notice] [pid 1488] AH00094: Command line: '/usr/sbin/apache2'[Sat Oct 15 11:58:04.666984 2016] [:error] [pid 1496] [client 192.168.1.2:38830] PHP Fatal error: Class