Adding support for Cumulus with Ignite

[networkop]

I think the title pretty much sums it up but since the PR is quite big, I'll try to break it down into multiple bullet points to better explain everything that has been affected:

• The main addition is the new runtime and node kind -- these are completely new files and don't change any of the existing interfaces or types
• Ability to specify runtime per node -- all nodes structs now have a private runtime field. This field is set during node.Init and defaults to the global runtime (as configured by the --runtime flag). However for cvx it defaults to a pre-defined ignite runtime with the ability to fall back to any other supported runtime via the NodeConfig.Runtime.
• As a result of the above, all of the calls to runtime (e.g. ListContainers) are now executed via a proxy functions defined for CLab, e.g. it is now c.ListContainers(ctx, labels) instead of c.Runtime(ctx, labels). CLab always knows about all of the configured runtimes (since it knows about all of the nodes).
• Topology parsing is moved to CLab.Init function -- this way it's safer to reason about CLab since we know that it'll always have Nodes and Runtimes parsed and initialized.

I think overall the last 3 points help enforce the separation between different packages and prevent direct calls between, e.g. cmd and runtime. It's much easier to read and troubleshoot code that relies on p2p interaction instead, i.e. cmd <-> clab <-> node <-> runtime.

AFAICT, none of the existing behavior has been affected, I've tried to make sure of that but happy to fix if there anything is off.

[karimra]

@networkop , did a first review, let me know if anything doesn't make sense to you.

If I got it right, cumulus uses ignite as a default runtime, but it supports docker ?
This could be confusing for users who will have to set the runtime explicitly to docker just for cvx nodes.

[networkop]

thanks @karima, will get the changes in shortly.

regarding the default behavior, with ignite you get 100% of cumulus features, which is why I made it a default behaviour. Ultimately, from user's pov it shouldn't be noticeable what runtime is used under the hood, they would still be able to interact with it the same exact way.

[networkop]

@karimra I've done multiple changes to address your comments. let me know what you think

[networkop]

@karimra @hellt all fixes have been pushed.

[karimra]

@networkop thanks for addressing all my comments, lgtm.

[networkop]

thanks @karimra . Can you check the latest commit? I think it would make sure runtimes are initialized only once.

[karimra]

Yes, even better, a single runtime passed to the node Init. Thanks

[hellt]

@networkop In 362dd1b I removed a few leftovers of log.Fatal

[networkop]

thanks @hellt . I also pushed a fix for the shortname parsing logic.

[hellt]

Solid work @networkop
I hope you had fun time ;) that is one of the biggest PRs in this repo

[networkop]

awesome! thanks for reviewing it @karimra @hellt