I've been annoyed these last few releases by high memory usage. Every day, my backups fail due to ENOMEM.
I have adjusted unicorn-worker-killer to undo the increased memory usage you did a few releases ago:
unicorn['worker_memory_limit_min'] = "300*(1024**2)"
unicorn['worker_memory_limit_max'] = "330*(1024**2)"
(8.9.0's default is a totally absurd 400-650MB.)and while that stops my server from falling over in the first 10 minutes, it does consistently fall over once a day.
Here is a screenshot of my htop, I'm not sure where to look next. 25% free sounds okay, but it's not enough to run a backup, or even run `gitlab-rake`.
http://weblinksdca.s3.amazonaws.com/Screen%20Shot%202016-07-...
How many unicorn workers are you using? For 2GB systems, I'd recommend at most 2 rather than the default 3. Some discussion about this is here: https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1279
We'll be doing more work in these coming months to profile and reduce the memory usage needed by GitLab so that all your tools can run comfortably in the 2GB range.
Currently, with Fluentd all I have to do is set the log-driver and tags in DOCKER_OPTS, point fluentd to ES, and I have all my container logs.
Does LogZoom work this seemlessly with docker? I know that at the very least I will need https://github.com/docker/docker/issues/20363 in order to implement any LogZoom plugin, so is this really much of a benefit if I don't have hundreds of containers running on a host? The only concern I had after reading this was if Fluentd will use as much resources as they mention. For my use case, I think not.
Regarding security with redis. Did you read the docs here? https://www.elastic.co/guide/en/logstash/current/plugins-out... Logstash does support Redis Password auth (as does Filebeat). Regarding the encryption with redis point, seeing as Redis doesn't support SSL itself, are you using spiped as the official Redis docs recommend?
Regarding the two queues, I would like to clarify that you can do this with the:
Filebeat -> Logstash -> Redis -> Logstash -> (outputs) technique.
If you declare two Logstash Redis outputs in the first 'shipper' Logstash you can write to two separate queues. And have the second 'indexer' read from both.
It is true that if one output is down we will pause processing, but you can use multiple processes for that. It is possible that in the near future we will support multiple pipelines in a single process (which we already do internally in our master branch for metrics, just not in a publicly exposed way yet).
Regarding JVM overhead. That's a fair point about memory. The JVM does have a cost. That said, memory / VMs are cheap these days, and that cost is fixed. One thing to be careful of is that we often times see people surprised to find that they get a stray 100MB event going through their pipeline due to an application bug. Having that extra memory is a good idea regardless. We have many users increasing their heap size far beyond what the JVM requires simply to handle weird bursts of jumbo logs.
In the past, we've also been burned by many Big Data solutions running out of heap space that adding more processes that relied on tuning JVM parameters again did not appeal to us.
I'm a bit confused as the assertion "This worked for a while, but when we wanted to make our pipeline more fault-tolerant, Logstash required us to run multiple processes.", is no more true for Logstash than it is for any other piece of software. Single processes can fail, so it can be nice to run multiples. It would be great if the author of the piece had clarified that further. If you're around I'd love to hear specifically what you mean by this. Internally Logstash is very thread friendly, we only recommend multiple processes when you want either greater isolation or greater fault tolerance.
I don't personally see what the difference is between:
Filebeat -> LogZoom -> Redis -> Logstash -> (Backends)
and
Filebeat -> LogStash -> Redis -> Logstash -> (Backends)
or even better
Filebeat -> Redis -> Logstash -> (Backends)
You can read more about the filebeat Redis output here: https://www.elastic.co/guide/en/beats/filebeat/current/redis...
Right, we considered using multiple Logstash processes, but we really didn't want to run three instances of Logstash requiring three relatively heavyweight Java VMs. The total memory consumption of a single VM running Logstash is higher than running three different instances of LogZoom.
We looked at the Filebeat Redis output as well. First, it didn't seem to support encryption or client authentication out of the box. But what we really wanted was a way to make Logstash duplicate the data into two independent queues so that Elasticsearch and S3 outputs could work independently.
We use it heavily to stream any Kind of Data into Kafka: Access and errorlogs, Application Logs, etc. Did you consider it as well?