-----Original Message----- Sent: Sunday, 20 June 2021 21:34 To: ceph-users@ceph.io Subject: *****SPAM***** [ceph-users] Re: Why you might want packages not containers for Ceph deployments

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3. Why is in this cephadm still being talked about systemd? Your orchestrator should handle restarts,namespaces and failed tasks not? There should be no need to have a systemd dependency, at least I have not seen any container images relying on this.

Podman uses systemd to manage containers so that it is daemonless, contrast with Docker where one has to maintain a separate daemon and use docker-specific tools to mange containers. If you assert that Podman should not exist, please take that up with the Podman folks.

If your OC uses systemd that means your OC is dependent on systemd and ceph not. Nobody here is discussing OC specifics.

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4. Ok found the container images[2] (I think). Sorry but this has ‘nothing’ to do with container thinking. I expected to find container images for osd, msd, rgw separately and smaller. This looks more like an OS deployment.

Bundling all the daemons together into one container is *genius*. Much simpler to build and maintain, one artifact vs a bunch. I wouldn’t be surprised if there are memory usage efficiencies too.

😃 what a non-sense. If building container images is a problem, do not even get involved with containers.

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7. If you are not setting cpu and memory limits on your cephadm containers, then again there is an argument why even use containers.

This seems like a non-sequitor. As many have written, CPU and memory limits aren’t the reason for containerizing Ceph daemons. If there are other container applications where doing so makes sense, that’s fine for those applications.

Indeed, so now we have concluded, cephadm does not use container functionality.

I suspect that artificial CPU limiting of Ceph daemons would have a negative impact on latency, peering/flapping, and slow requests. Ceph is a distributed system, not a massively parallel one. OSDs already have a memory target that can be managed natively, vs an external mechanism that arbitrarily cuts them off at the knees when they need it the most. That approach would be addressing the symptoms, not the root cause. Having been through a multi-day outage that was substantially worsened by the OOMkiller (*), I personally want nothing to do with blind external mechanisms deciding that they know better than Ceph daemons whether or not they should be running. If your availability and performance needs favor rigidly defined areas of doubt and uncertainty, that’s your own lookout.

Agreed, no real need for a using containers.

* A release that didn’t have OSD memory target setting yet. Having that would have helped dramatically.

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8. I still see lots of comments on the mailing list about accessing logs. I have all my containers log to a remote syslog server, if you still have your ceph daemons that can not do this (correctly). What point is it even going to containers.

With all possible respect, that’s another non-sequitor, or at the very least, an assumption that your needs are everyone’s needs. Centralized logging makes sense in some contexts. But not always, and not to everyone. Back around the Hammer or Jewel releases there was a bug where logging to syslog resulted in daemon crashes. I haven’t tried it with newer releases, but assume that’s long been fixed.

I’m not a an [r]syslog[ng] expert by far, but I suspect that central- only logging might not deal well with situations like an OSD spewing entries when the debug subsystem level is elevated. Moreover, many of the issues one sees with Ceph clusters are network related. So when there’s a network problem, I want to rely on the network to be able to see logs? I’ve seen syslog drop entries under load, something I personally wouldn’t want for Ceph daemons. There are of course many strategies between the extremes.

So your arguing is, if it does not work in <5% let's not use it?

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9. I am updating my small cluster something like this:

I’m guessing you’ve never updated between major releases. That process tends to have additional steps and nuances, which is one of the compelling arguments in favor of orchestration: when it’s done well, most operators don’t need to rev their own homebrew orchestration to set the right flags at the right time, etc. But one of the great things about OSS is that you have the flexibility to roll you own if you so choose.

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I am never going to run a ‘ceph orch upgrade start –ceph-version 16.2.0’. I want to see if everything is ok after each command I issue. I want to see if scrubbing stopped, I want to see if osd have correctly accepted the new config.

So you want to do all the things that an orchestrated rolling upgrade does for you. Check.

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I have a small cluster so I do not see this procedure as a waste of time. If I look at your telemetry data[3]. I see 600 clusters with 35k osd’s, that is an average of 60 osd per cluster. So these are quite small clusters, I would think these admins have a similar point of view as I have.

Careful with those inferences.

We are not operating here on some website cpanel project. Due to the size of these storage solutions one should expect lots of third party data is stored there. So I would argue you should not want to have 'I only know Kubernetes commands' sysadmins operating ceph.

* Operators who submit telemetry may not be a representative sample * Sites may have many more than one cluster, If one has a 20 OSD lab cluster and a 1000 OSD production cluster, perspectives and processes are going to be different than someone with a single 60 OSD cluster. * Average != median

Whatever, prove me wrong in that not the vast majority of clusters are small. Logics just dictates this.

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I am rather getting the impression you need to have an easy deployment tool for ceph than you want to really utilize containers. First there was this ceph-deploy and ceph-ansible which I luckily skipped both

That’s more than a little harsh. A lot of people get a lot of value out of those tools.

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The ceph daemons seem to be not prepared for container use, ceph containers can’t use cpu/memory limits

They don’t make julienne fries either. What of it?

So the argument for cephadm to move to containers is non-sense. If there would be a true container aspiration, you would have to want to apply at least a few of the suggestions.

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And last but not least you totally bypass that the (ceph) admin should choose the OC platform and not you, because he probably has more than just ceph nodes.

Nobody’s stopping you from rolling your own containers, using traditional packages, or heck even deploying with tarballs. That’s the beauty of OSS. Let’s leave Orange County out of it though.

I agree, there should be no strong relationship between ceph and any OC. I tend to think that Kubernetes or other OC's should be responsible for offering a ceph implementation.

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So my question to you: What problem is it actually that your cephadm dev team is trying to solve? That is not clear to me.

Asked and answered, sir

Could you write it to me like I am six year old? I do not get from your text what problem the cephadm team is trying to solve.