Re:WTF is a container?
by moondev on Monday October 17, 2016 @01:30PM
(#12727140)
The problem is you are trying to run a production environment with a development tool. Manually doing "docker run" is not how you deploy containers. Kubernetes is designed to run containers and addresses the most common issues.
> Making containers work together, for example we use a logging agent, we decided to make that its own container. Then actually getting a way to share a log directory with the agent, was very painful and unclear. (Honestly the single most frustrating thing i recall was asking for advice in irc and more or less being told i am doing it wrong)
kubernetes handles shared directories easily with all containers in a pod. If you need to share across pods you can use persistentVolumeRequests
> Containers would randomly crash under load exiting with error 137 out of memory. Apparently a few of our services would randomly leak memory, but only when running inside a docker container vs ubuntu 14.04. (I never figured this out)
Kubernetes provides replication controllers that will always re-launch or provision the number of desired pods for a service. It also provides health checks just like an aws elb to determine if a pod is healthy. You can also set resource limits (cpu and memory) per pod.
> Random hanging issues, suddenly docker exec is hanging. Being told to revert to an older version, or install a newer version is tiring and makes my environment very inconsistent.
Docker exec should not really be used on a running service in production, all of your provisioning should happen in the dockerfile to build the image
> Trying to debug why our app in the container isn't working is not fun at all.
If your application is 10-factor, you can easily tail the logs of any container at anytime
> Making containers work together, for example we use a logging agent, we decided to make that its own container. Then actually getting a way to share a log directory with the agent, was very painful and unclear. (Honestly the single most frustrating thing i recall was asking for advice in irc and more or less being told i am doing it wrong)
kubernetes handles shared directories easily with all containers in a pod. If you need to share across pods you can use persistentVolumeRequests
> Containers would randomly crash under load exiting with error 137 out of memory. Apparently a few of our services would randomly leak memory, but only when running inside a docker container vs ubuntu 14.04. (I never figured this out)
Kubernetes provides replication controllers that will always re-launch or provision the number of desired pods for a service. It also provides health checks just like an aws elb to determine if a pod is healthy. You can also set resource limits (cpu and memory) per pod.
> Random hanging issues, suddenly docker exec is hanging. Being told to revert to an older version, or install a newer version is tiring and makes my environment very inconsistent.
Docker exec should not really be used on a running service in production, all of your provisioning should happen in the dockerfile to build the image
> Trying to debug why our app in the container isn't working is not fun at all.
If your application is 10-factor, you can easily tail the logs of any container at anytime