Node Stages and Dependency Manager

[steiler]

Implementing #1700

This change will first of all execute the Post-Deploy phase as another step in the scheduleNode func.
This will allow for a wider variety of dependencies. e.g. just deploying a node when another is already healthy.
Further the new struct for WaitFor allows to wait for specific states of other nodes, before certain deployment stages are started.
Multiple dependencies for different or the same phase are also possible.

So the structure of the WaitFor field changes as follows:

    NodeC:
      ...
      wait-for:
        create:                    # For NodeB to enter the _create_ stage, the following preconditions must be met
          - node: NodeA            # NodeA
            phase: healthy         # Must have entered the healthy
        configure:                 # For NodeB to enter the _configure_ stage, the following preconditions must be met
          - node: NodeB            # NodeB
            phase: create          # Must have finished the _create_ stage

These phases are used in two means.

  wait-for:
    create:                      # Means 1
      - node: xyz
        phase: healthy           # Means 2

Means 1 defines what needs needs to happen before the node enters the Means 1 phase / stage.
Means 2 on the other hand defined which phase / stage node xyz must have finished for the enclosing node to start the Means 1 phase / stage.

The available phases are:

• create - Container create and start
• create-links - Deploy container links
• configure - Deploy container configuration
• healthy - Container turns healthy (only viable as a Means 2 statement)
• exit - Container exists (usefull for init containers, also only viable as Means 2 statement

Taking a look at this example:

name: linux

topology:
  kinds:
    linux:
      image: alpine
      cmd: sleep infinity
  nodes:
    l1:
      kind: linux
    l2:
      kind: linux
      wait-for:
        configure:
          - node: l1
            phase: create
    l3:
      kind: linux
      image: mavatest
      wait-for:
        create:
          - node: l2
            phase: configure
    l4:
      kind: linux
      wait-for:
        create:
          - node: l3
            phase: healthy
        configure:
          - node: l1
            phase: configure

Node l1 starts without any dependency. For l2 to enter the configure/post-deploy stage, l1 is required to have finished the create phase.
Further l3 will start its creation as soon as node l2 finished its configure/post-deploy stage. l4 will get created as soon as l3 turned healthy (make sure healthchecks are enabled*) and node l1 is done with its configure phase.

*We have the healthcheck PR still pending, that enables you to define healthchecks as part of the topology or you rely on healthcheck defined already via the Dockerfile -> Healthcheck

[steiler]

CAREFULL, the structure of the topo file has changed to what is documented in the top.
It now follows the structure @hellt suggested further up.

[hellt]

@steiler also check out this commit
580e852

I think it makes things clearer, as no extra indirection is involved, no Enter/SignalDone on the depMgr level, these function belong to the dependencyNode

[steiler]

@steiler also check out this commit 580e852

I think it makes things clearer, as no extra indirection is involved, no Enter/SignalDone on the depMgr level, these function belong to the dependencyNode

Yes that is alright. Would be a natural change in the upcoming change, we discussed. But it's fine to do it right now.

[codecov]

Codecov Report

Attention: 96 lines in your changes are missing coverage. Please review.

Comparison is base (f49b4c8) 53.43% compared to head (6dad097) 53.66%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1759      +/-   ##
==========================================
+ Coverage   53.43%   53.66%   +0.23%     
==========================================
  Files         152      154       +2     
  Lines       11070    11236     +166     
==========================================
+ Hits         5915     6030     +115     
- Misses       4314     4346      +32     
- Partials      841      860      +19     

Files	Coverage Δ
nodes/node.go	57.14% <ø> (ø)
runtime/runtime.go	79.41% <ø> (ø)
types/node_definition.go	94.05% <100.00%> (ø)
types/types.go	61.53% <ø> (ø)
clab/config.go	67.00% <33.33%> (-0.46%)	⬇️
clab/dependency_manager/dependency_node.go	95.55% <95.55%> (ø)
clab/exec/exec.go	63.93% <80.00%> (+1.10%)	⬆️
cmd/deploy.go	67.74% <50.00%> (+1.39%)	⬆️
runtime/ignite/ignite.go	0.40% <0.00%> (-0.01%)	⬇️
runtime/docker/docker.go	70.94% <42.85%> (-0.34%)	⬇️
... and 6 more