Every week the Kubernetes contributing community meet virtually over Google Hangouts. We want anyone who's interested to know what's discussed in this forum.
Here are the notes from today's meeting:
- Eric Paris: replacing salt with ansible (if we want)
- In contrib, there is a provisioning tool written in ansible
- The goal in the rewrite was to eliminate as much of the cloud provider stuff as possible
- The salt setup does a bunch of setup in scripts and then the environment is setup with salt
- This means that things like generating certs is done differently on GCE/AWS/Vagrant
- For ansible, everything must be done within ansible
- Background on ansible
- Does not have clients
- Provisioner ssh into the machine and runs scripts on the machine
- You define what you want your cluster to look like, run the script, and it sets up everything at once
- If you make one change in a config file, ansible re-runs everything (which isn’t always desirable)
- Uses a jinja2 template
- Create machines with minimal software, then use ansible to get that machine into a runnable state
- Sets up all of the add-ons
- Eliminates the provisioner shell scripts
- Full cluster setup currently takes about 6 minutes
- CentOS with some packages
- Redeploy to the cluster takes 25 seconds
- Questions for Eric
- Where does the provider-specific configuration go?
- The only network setup that the ansible config does is flannel; you can turn it off
- What about init vs. systemd?
- Should be able to support in the code w/o any trouble (not yet implemented)
- Discussion
- Why not push the setup work into containers or kubernetes config?
- To bootstrap a cluster drop a kubelet and a manifest
- Running a kubelet and configuring the network should be the only things required. We can cut a machine image that is preconfigured minus the data package (certs, etc)
- The ansible scripts install kubelet & docker if they aren’t already installed
- Each OS (RedHat, Debian, Ubuntu) could have a different image. We could view this as part of the build process instead of the install process.
- There needs to be solution for bare metal as well.
- In favor of the overall goal -- reducing the special configuration in the salt configuration
- Everything except the kubelet should run inside a container (eventually the kubelet should as well)
- Running in a container doesn’t cut down on the complexity that we currently have
- But it does more clearly define the interface about what the code expects
- These tools (Chef, Puppet, Ansible) conflate binary distribution with configuration
- Containers more clearly separate these problems
- The mesos deployment is not completely automated yet, but the mesos deployment is completely different: kubelets get put on top on an existing mesos cluster
- The bash scripts allow the mesos devs to see what each cloud provider is doing and re-use the relevant bits
- There was a large reverse engineering curve, but the bash is at least readable as opposed to the salt
- Openstack uses a different deployment as well
- We need a well documented list of steps (e.g. create certs) that are necessary to stand up a cluster
- This would allow us to compare across cloud providers
- We should reduce the number of steps as much as possible
- Ansible has 241 steps to launch a cluster
- 1.0 Code freeze
- How are we getting out of code freeze?
- This is a topic for next week, but the preview is that we will move slowly rather than totally opening the firehose
- We want to clear the backlog as fast as possible while maintaining stability both on HEAD and on the 1.0 branch
- The backlog of almost 300 PRs but there are also various parallel feature branches that have been developed during the freeze
- Cutting a cherry pick release today (1.0.1) that fixes a few issues
- Next week we will discuss the cadence for patch releases