OCI symlink and path updates

[johnalotoski]

Description

This PR makes improvements to the cardano-node and cardano-submit-api oci images in the following ways:

New Features

• Additional network configs in the node image:

  • Previously, the node image only had network configuration available in the nix store at non-predictable paths, except for mainnet config and topology, copied to /opt/cardano/config/mainnet-{config,topology}.json
  • Iohk-nix generated configuration files for mainnet, preprod and preview networks are now available at /opt/cardano/config/$NETWORK/ with the tree of configuration for an example NETWORK looking like:

    /opt
    └── cardano
        ├── config
        │   ├── $NETWORK
        │   │   ├── alonzo-genesis.json
        │   │   ├── byron-genesis.json
        │   │   ├── config-bp.json
        │   │   ├── config.json
        │   │   ├── conway-genesis.json
        │   │   ├── db-sync-config.json
        │   │   ├── mithril-signer-config.json
        │   │   ├── shelley-genesis.json
        │   │   ├── submit-api-config.json
        │   │   └── topology.json
        ├── index.html
        ├── ...
        └── rest-config.json
    

  • The legacy path /opt/cardano/config/mainnet-{config,topology}.json config files are symlinked to this new config structure for backwards compatibility.

• A new merge mode in the node image:

  • "Scripts" mode offers a fixed default config and topology to run node whereas "custom" mode offers a fully customized config and topology which require submitting full config and/or topology files.
  • For those wanting to make small changes to the base config, "merge" mode deep merges config and/or topology customization to the base config. See the nix/docker/README.md for details.

Documentation

• Docs detailing the modes of the node image (scripts, custom, merge and cli) were improved. Docs were moved from mostly being in nix files to the nix/docker/README.md where most would expect to find them.

Inconsistencies Addressed

• Previously, default paths varied by node image operating mode as well as image (node vs. submit-api) which has led to confusion when docker mountpoint and volume commands fail to produce expected results.
• To improve consistency the following changes are made:
  • Node's "custom" mode has /opt/cardano/{data,ipc,logs} symlinked to root /{data,ipc,logs}
    • These symlinks make docker guest path mountpoints of /{data,ipc,logs} usable with all modes
  • All database state path defaults were updated to /data/db
  • All ipc default path mountpoints were updated to /ipc and the node socket file path to /ipc/node.socket
    • The submit-api image has /node-ipc now symlinked to /ipc for backwards compatibility.

Breaking Changes

• With the consistency changes above, some environment variable defaults were changed. If these are problematic for a downstream consumer, they can be overridden by setting the env var back to what is desired, for example in a docker cli run command with -e ENVNAME=<...>. These breaking changes are:

For "custom" and "merge" modes:
  *  CARDANO_DATABASE_PATH env var default changed:
    * From: /opt/cardano/data
    * To: /data/db

  * CARDANO_SOCKET_PATH env var default changed:
    * From: /opt/cardano/ipc/socket
    * To: /ipc/node.socket

  * GENESIS_JSON env var default changed:
    * From: $CARDANO_CONFIG_BASE/mainnet-shelley-genesis.json
    * To: $CARDANO_CONFIG_BASE/mainnet/shelley-genesis.json

For "client" mode:
  * CARDANO_NODE_SOCKET_PATH env var default changed:
    * From: /opt/cardano/ipc/socket
    * To: /ipc/node.socket

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• CI passes. See note on CI. The following CI checks are required:
• Self-reviewed the diff