I can run multiple sidekiq processes each one process queues for a specific Rails application.
But if I have 10 applications then it will be always running 10 Sidekiq processes each one consuming memory.
How to run only one Sidekiq process which will serve multiple applications?
Related
I ran htop in my production server to see what was eating my RAM. A lot of sidekiq process is running, is this normal?
Press Shift-H. htop shows individual threads as processes by default. There is only one actual sidekiq process.
You seem to have configured it to have 25 workers.
By default, one sidekiq process creates 25 threads.
If that's crushing your machine with I/O, you can adjust it down:
sidekiq -c 10
https://github.com/mperham/sidekiq/wiki/Advanced-Options
If you are not using JRuby then it's likely these all are seperate processes that consume memory.
I've two Rails application running on two different instance(lets say Server1 and Server2) but they have similar codes and shares the same Postgresql DB.
I installed Sidekiq and pushing the jobs in Queue from both the servers, but I'm running the Sidekiq process only in Server1.
I've single Redis server and its running on Server1 which shares the Redis with Server2.
If a job pushed from Server2 it getting processed in Server1's Sidekiq process and its what I actually wanted.
My question is
How the Sidekiq process on Server1 knows that a job is pushed in Redis?
Whether the Sidekiq process continuously checks on the Redis server for any new jobs or the Redis server is intimating to the Sidekiq process about the new job?
I got confused and amazed about this!!!
Could anyone please clarify the Sidekiq's process to get the job from Redis server?
It will be helpful for newbies like me.
Sidekiq uses redis command named BRPOP.
This command gets an element from a list (which is your job queue). And if the list is empty, it waits for element to appear and then pops/returns it. This also works with multiple queues at the same time.
So no, sidekiq does not poll redis and redis does not push notifications to sidekiq.
Sidekiq uses a polling mechanism to check for new jobs in Redis. The default polling interval is set at 5 seconds and can be adjusted in the configuration file located at lib/sidekiq/config.rb [link]
# lib/sidekiq/config.rb
average_scheduled_poll_interval: 5
By the way, jobs are stored in Redis as a list and Sidekiq retrieves them by using the BRPOP (Blocking Right Pop) command to avoid any race conditions. This ensures that multiple Sidekiq processes running on different instances are able to retrieve the jobs in a coordinated manner.
I am currently working on moving my environment off Heroku and part of my application is runs a clock process that sets off a Sidekiq background job.
As I understand it, Sidekiq is composed of a client, which sends jobs off to be queued into Redis and a server which pulls off requests of the queue and processes them. I am now trying to split out my application into the following containers on Docker:
- Redis container
- Clock container (Using Clockwork gem)
- Worker container
- Web application container (Rails)
However, I am not sure how one is supposed to split up this Sidekiq server and client. Essentially, the clock container needs to be running Sidekiq on it so that the client can send off jobs to the Redis queue every so often. However, the worker containers should also run Sidekiq (the server though) on them so that they can process the jobs. I assume that splitting up the responsibilities between different containers should be quite possible to do since Heroku allows you to split this across various dynos.
I can imagine one way to do this would be to assign the clock container to pull off a non-existent queue so that it just never pulls any jobs off the queue and then set the worker to be pulling off a queue that exists. However, this just doesn't seem like the most optimal approach to me since it will still be checking for new jobs in this non-existing queue.
Any tips or guides on how I can start going about this?
The sidekiq client just publishes jobs into redis. A sidekiq deamon process just subscribes to redis and starts worker threads as they are published.
So you can just install the redis gem on both conatainers: Clock container and Worker Container and start the worker daemon only on the Worker Container and provide a proper redis config to both. You also have to make sure that the worker sourcecode is available on both servers/containers as Sidekiq client just stores the name of the worker class and then the daemon instanciates it through metaprogramming.
But actually you also can just include a sidekiq daemon process together with every application wich needs to process a worker job. Yes, there is this best practise of docker for one container per process, however imho this is not an all or nothing rule. In this case i see both processes as one unity. It's just a way of running some code in background. You then would just configure that instances of same applications just work against same sidekiq queues. Or you could even configure that every physical node runs again a separate queue.
What is the best way to manage multiple interconnected services for a web applications like:
rails server / unicorn / puma
redis / sidekiq / resque
So that, if one is stopped or started, others get stopped/started too.
Usually a monitoring tool is used for this purpose. One such good tool is God.
The basic idea is to run God as a system service, and configure your sidekiq to be watched by God. When your server restarts, God runs as a service and it will start your sidekiq workers.
You have more benefits by using God, to name just a few:
notifications: you can configure it to send you notifications when your sidekiq worker dies and gets restarted.
resource monitoring: you can configure it to take actions based on predefined rules. For example, restart the job when it consumes too much memory.
Update: just read an article this morning which might be very helpful: Create, run and manage your Ruby background processes with upstart.
My Rails application has a number of tasks which are offloaded into background processes, such as image resizing and uploading to S3. I'm using delayed_job to manage these processes.
These processes, particularly thumbnailing PDFs (using Ghostscript) and resizing images (using ImageMagick), are CPU intensive and often consume 100% CPU time. Since these jobs are running on the same (RedHat Linux) server as the web application itself, as well as the DB, they can lead to our web application being unresponsive.
One solution is to get another server on which to run only the background jobs. I guess this would be the optimal solution? However, since this isn't something I can do immediately I wonder whether it would be possible to somehow make the background jobs run at a lower operating system priority, and hence consume less CPU cycles in doing their work?
Thoughts appreciated.
If I'm not mistaken, delayed_job uses worker processes that will handle all the background jobs. It should be easily possible to alter the OS scheduling priority of the process when you start it.
So instead of, for example:
ruby script/delayed_job -e production -n 2 start
try:
nice -n 15 ruby script/delayed_job -e production -n 2 start