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Developer Clusters HOWTO

This document describes how to launch a Cardano cluster on AWS from scratch.

Intended audience

This document is to support developers in their need to deploy ad hoc clusters.


  1. SSH access to the staging deployer


  1. cardano-sl git revision hash.
  2. iohk-ops branch. In absence of preference, the default is master.
  3. Issue ID being worked on.


Note that io is an alias to iohk-ops which becomes available when you enter the nix-shell.

Replace ISSUE-ID with your issue ID, or any name to identify the cluster. This should all be in lowercase to avoid problems when updating DNS entries.

  1. SSH to the staging jumpserver.
  2. iohk-ops clone ISSUE-ID — the branch defaults to master.
  3. cd ISSUE-ID
  4. optional: git checkout SOME-BRANCH
  5. iohk-ops set-rev cardanosl CARDANO-REVISION
  6. nix-shell -A withAuxx
  7. io new [--dont-generate-keys] [--configuration-key CONFIGURATION-KEY] ISSUE-ID Nodes [Explorer]

    • the CONFIGURATION-KEY defaults to devnet
    • this will generate stake keys using cardano-keygen, unless --dont-generate-keys was passed
    • the elements after ISSUE-ID name cluster components, for the CSL nodes, explorer and report server, correspondingly — which all are, strictly speaking, optional, with the caveat that having a Nodes-free cluster doesn’t make a lot of sense
  8. io deploy, with following optional arguments:

    • --bump-system-start-held-by 15 — bump --system-start by N minutes from now, where now is the moment when the deploy subcommand starts to execute (which might be later than the invocation of the io command itself, due to command pipelining)
  9. Make sure to use io destroy --confirm delete after you are done with the cluster to destroy the Nixops deployment — all the local files remain intact.

Obtaining journals

systemd-journald journals can be obtained — either cluster-wide, or from a single node:

iohk-ops [--on u-a-1] -c staging-testnet.yaml get-journals [--since "2017-11-18 21:10:00 UTC"] [--until "2017-11-18 21:40 UTC"]


  • --on NODE-NAME
  • --since JOURNALD-TIME-SPEC, defaults to 6 hours ago
  • --until JOURNALD-TIME-SPEC, defaults to unspecified (essentially now)

Restarting cluster faster, without full machine redeployment

When one wants to redeploy a cluster, it’s not necessary to destroy the machines and redeploy them from scratch: typically the following will suffice:

io deploy --build-only     # only need this on deployments of new cardano commits
io stop wipe-node-dbs --confirm wipe-journals deploy --bump-system-start-held-by 5

Operating a cluster with directly-specified, non-generated genesis

  1. The genesis JSON file must be referred to from the configuration.yaml for the cardano-sl commit specified in cardano-sl-src.json.
  2. Secret keys need to be placed at keys/, where N ranges in 0..k-1, where k is the number of nodes.
  3. io new needs be passed --dont-generate-keys
  4. io deploy needs NOT be passed --bump-system-start-held-by

Connect a wallet to the developer cluster

This uses the customizable wallet connect script generator in cardano-sl (see Exchange Onboarding).

You need to clone the cardano-sl repository and checkout the particular commit used in io set-rev (see rev attribute of cardano-sl-src.json):

  1. git clone && cd cardano-sl
  2. git checkout CARDANO-REVISION

Important: make sure you are in the cardano-sl directory not iohk-ops — otherwise the parameters won’t take effect.

Create a file called custom-wallet-config.nix with the following contents:

  walletListen = "";

  ## Directory for the wallet's local state.
  ## must be enclosed in double quotes.
  stateDir = "./state-wallet-fragment";

  ## Set this to the DNS name of the relay in the dev cluster.
  relays = "";

  # Selects the "devnet" configuration,
  environment = "override";
  confFile = ./lib/configuration.yaml;
  confKey = "devnet";

   # A dummy value is required or the wallet will fail.
   additionalNodeArgs = "--system-start 1";

That file contains the parameters for building the connect script. If the parameters change, then the connect script needs to be built again. To build the connect script:

nix-build -A connectScripts.demoWallet -o ./

Run the wallet and it will connect to the developer cluster.