Perl Mojo Hypnotoad server has a hot restart feature. To update a program you only need to start Hypnotoad again and it eventually will replace all running copies.
How to tell Supervisor that there is no need to stop my server while restarting it?
I don't know correct answer, but i want to try to answer...
The restart of supervisord takes place in two stages:
stop
start
So, according to mojo docs and supervisord docs (see to stopsignal) you need to do something like this:
stopsignal=QUIT
stopwaitsecs=20000 # big number, it very depend from your project, because don't know how much time need to close all exsisting connections
Optionaly you may to add this options:
stopasgroup=true
killasgroup=true
Related
I have a process running on a server.
FYI I'm trying to solve the same problem for both nodejs and Python - I don't really think the specific server/languages matters as the question is more about approach to deployment.
The work the the process does might take anywhere from seconds to hours to run.
I'm trying to work out how to deploy updated code for the process.
I don't want to just stop the process in the middle of what it is doing for fear of losing all the work done so far in the long running process.
So what's a good way to get the process to gracefully exit and restart when new code has arrived?
I use systemd for running the nodejs service.
I use Ansible to deploy updates, not that this is really relevant.
I thought maybe at the end of each execution of the long running process the server could check to see if some file has been placed on the disk as some sort of flag to indicate it should exit and restart, but that seems kinda brittle and hacky.
Anyone got any better mechanisms for this sort of thing?
I'd like to be able to gracefully restart the Minion worker I am working on developing (i.e.: without gong back to the command line, killing it and restarting it, which is what I do now).
Is that possible? I'm hoping for something similar to what one can do with a Plack server, i.e.: sending a HUP signal restarts the server.
See this proposed feature - though nobody has worked on it yet.
I have a node app in bluemix which holds some transaction cache in memory and I would like to flush this cache to DB before the application goes down. So I have the appropriate event handlers to intercept SIGTERM/SIGINT signals and all works fine from my laptop, however, it seems like the cf stop command does not perform graceful shutdown.
Unfortunately, there is no clear documentation around this topic, at one place in the cloudfoundary app-lifecycle doc they do mention that first SIGTERM is issued and then wait for 10 secs etc but Im not seeing this happening. Probably a bug on their side. https://docs.cloudfoundry.org/devguide/deploy-apps/app-lifecycle.html
Has anyone noticed this issue and probably have a workaround pls?
CF is sending the SIGTERM first but because of how the app is started by other processes, it's not being correctly propagated to your app.
As a workaround, disable App Management by setting the CF environment variable BLUEMIX_APP_MGMT_INSTALL=false and prefix your app's start command in your package.json file with 'exec' (e.g. exec node app.js).
I am working with Apache Kafka and using distributed worker. I can start my worker as below:
// Command to start the distributed worker.
"bin/connect-distributed.sh config/connect-distributed.properties"
This is from official documentation. After this we can create connectors and tasks. And this works fine.
But when i change my connector or task logic I should add new jar to classpath of kafka. And after this I should restart worker.
I don't know how it should be right I think we should stop and run worker.
But when I want to stop worker I don't know how i can do it correctly.
ofcourse, I can find my process by ps aux | grep worker, kill it and kill rest server which i should find by ps too. But i think it's strange case. Killing two processes isn't good idea, but i can't find any information how we can do it in another way.
If you know right way, please help me:)
Thanks for your time.
Killing two processes isn't good idea
ConnectDistributed is only one process. There is no separate REST server to stop.
And yes, :connector/pause followed by a kill <pid> is the correct way to stop it.
If installed with a recent version of Confluent Platform, you can stop/start using systemctl.
I've got a Perl based FastCGI app that rarely goes down. However, when it does go down, the restart is not automatic. Restarting Apache manually always does the trick but that does address improving the uptime of the app.
I'm thinking of using a cron job in conjunction with a script that uses WWW::Mechanize to periodically check on the app and restart it as required, as suggested by the folks at Perl Monks :
Keep FastCGI Processes Up and Running
Before I do that, I'm want to know if anyone knows of better ways to monitor a FastCGI process and restarting it automatically when it dies, or is the method suggested above the optimal one?
Thanks.
Monit is a nice monitoring daemon that can do automatic restarts and/or notification.
How about not having the process supervised by Apache but using an mechanism similar to the way init(8) starts getty processes? I have found daemon to be quite useful.
Most of the web servers offer already offer this as a configuration option.