Run a node on a server with Ubuntu on Testnet#
This guide describes how organizations can run a node on the Concordium network from a server and how to set up the node to run as a validator node.
You can also watch the video to learn how to run a node with Ubuntu.
Ubuntu 20.04 or 22.04 must be installed on the server that is running the node.
The server must be running around the clock.
If you want to run the node as a validator, you must have generated validator keys.
Subscribe to the Testnet status page and the release information on Discourse to stay informed about updates and changes that may affect you as a node runner, including node software releases and protocol updates.
To subscribe to updates on the Testnet status page click Subscribe to get all updates or click Get updates to choose to get all updates or only updates for specific products.
Install the Debian package and run a node#
To run the node, you must install a Debian package.
After installation, the
concordium-testnet-node-collector services will be started.
The services are also enabled to start automatically on system start.
Download the Debian package
Install the package:
$sudo apt install /path-to-downloaded-package
path-to-downloaded-packageis the location of the downloaded
The path should be absolute, e.g.,
aptwill assume that you want to install a package from the registry.
node namewhen prompted. The node name is visible on the network dashboard. When you have installed the services, the
concordium-testnet-nodewill be running automatically.
To verify that the node is running, go to the Concordium dashboard and look for a node with the name you provided.
concordium-testnet-node service that you just installed will be running around the clock, except if you’re going to restart the node with validator keys.
If you want more detailed information about building and maintaining a node, or if your node is not running, see the Building .deb packages for ubuntu distributions README from Concordium
Enable inbound connections#
If you are running your node behind a firewall, or behind your home router, then you will probably only be able to connect to other nodes, but other nodes will not be able to initiate connections to your node. This is perfectly fine, and your node will fully participate in the Concordium network. It will be able to send transactions and, if so configured, to produce blocks.
However you can also make your node an even better network participant
by enabling inbound connections. By default,
8889 for inbound connections on Testnet. Depending on your network and
platform configuration you will need to forward an external port
8889 on your router, open it in your firewall, or both. The
details of how this is done will depend on your configuration.
Synchronize a node with the network#
When you start a node for the first time, it can take a while to synchronize the node with the rest of the network, since it has to get all blocks from its peers. That is why all node distributions since 6.1 come with out of band catchup enabled. This will speed up the initial catchup and during out of band catchup the node will not have any peers.
The out of band catchup can be kept enabled even after the node is caught up,
but is not necessary. To disable out of band catchup unset the
CONCORDIUM_NODE_CONSENSUS_DOWNLOAD_BLOCKS_FROM environment variable as show in step 3 below.
Stop the node if it is running$sudo systemctl stop concordium-testnet-node.service
Edit the node service configuration file$sudo systemctl edit concordium-testnet-node.service
Add the following under the
[Service]section (create the section if it does not exist)UnsetEnvironment=CONCORDIUM_NODE_CONSENSUS_DOWNLOAD_BLOCKS_FROM
Start the service again$sudo systemctl start concordium-testnet-node.service
After the node is caught up remove the out of band catchup configuration to speed up further node restarts.
Node collector configuration#
Since version 5.3.2 of the node, the collector uses the GRPC V2 interface. Therefore, in order to run the collector, it is required that the node which the collector connects to has the GRPC V2 interface enabled.
Since the GRPC V2 port is different than the GRPC V1 port, you might need make changes to your node configuration. You only need to change the collector port if you have overridden your node configuration. You can edit your overrides with:
$ sudo systemctl edit concordium-testnet-node.service
This will open your overrides in your default editor. Below is an example for the default testnet port
If the node is configured with TLS, then CONCORDIUM_NODE_COLLECTOR_GRPC_HOST must be configured such that it uses the domain of the certificate, for example,
When upgrading, you can only upgrade one minor version at a time, or from the last release of major version X to major version X+1. You cannot skip versions. For patches, you can skip versions e.g. X.X.0 to X.X.3, or X.1.1 to X.2.3. To download previous node versions, see Previous node versions.
To upgrade to a newer version of the concordium-testnet-node package you need to:
Install the new package
$apt install ./concordium-testnet-node_(version)_amd64.deb
This step performs automatic database migration, so that the new node doesn’t have to catch up from scratch. After installation is completed, the node and the collector are started as before.