Cosmovisor

The Cosmos team provides a tool named Cosmovisor that allows your node to perform some automatic operations when needed. This is particularly useful when dealing with on-chain upgrades, because Cosmovisor can help you by taking care of downloading the updated binary and restarting the node for you.

If you want to learn how to setup Cosmovisor inside your full or validator node, please follow the guide below.

Setup

1. Downloading Cosmovisor

To install the latest version of cosmovisor, run the following command:

go install github.com/cosmos/cosmos-sdk/cosmovisor/cmd/cosmovisor@latest

To install a previous version, you can specify the version.

go install github.com/cosmos/cosmos-sdk/cosmovisor/cmd/[email protected]

You can also install from source by pulling the cosmos-sdk repository and switching to the correct version and building as follows:

git clone [email protected]:cosmos/cosmos-sdk
cd cosmos-sdk
git checkout cosmovisor/vx.x.x
cd cosmovisor
make

This will build cosmovisor in your current directory. Afterwards you may want to put it into your machine's PATH like as follows:

cp cosmovisor ~/go/bin/cosmovisor

To check your cosmovisor version, you can use this command and make sure it matches the version you've installed:

strings $(which cosmovisor) | egrep -e "mod\s+github.com/cosmos/cosmos-sdk/cosmovisor"

Note: If you are using go v1.15 or earlier, you will need to use go get, and you may want to run the command outside a project directory.

2. Setting up environmental variables

Cosmovisor relies on the following environmental variables to work properly:

• DAEMON_HOME is the location where upgrade binaries should be kept (e.g. $HOME/.desmos).
• DAEMON_NAME is the name of the binary itself (eg. desmos).
• DAEMON_ALLOW_DOWNLOAD_BINARIES (optional, default = false) if set to true will enable auto-downloading of new binaries (for security reasons, this is intended for full nodes rather than validators).
• DAEMON_RESTART_AFTER_UPGRADE (optional, default = true) if set to true it will restart the sub-process with the same command line arguments and flags (but new binary) after a successful upgrade. By default, cosmovisor dies afterwards and allows the supervisor to restart it if needed. Note that this will not auto-restart the child if there was an error.
• DAEMON_POLL_INTERVAL (optional, default = 300ms) is the interval length for polling the upgrade plan file. The value can either be a number (in milliseconds) or a duration (e.g. 1s).
• UNSAFE_SKIP_BACKUP (optional, default = false), if set to true, upgrades directly without performing a backup. Otherwise (false) backs up the data before trying the upgrade. The default value of false is useful and recommended in case of failures and when a backup needed to rollback. We recommend using the default backup option UNSAFE_SKIP_BACKUP=false.

To properly set those variables, we suggest you to edit the ~/.profile file so that they are loaded when you log into your machine. To edit this file you can simply run

sudo nano ~/.profile

Once you're in, we suggest you to set the following values:

export DAEMON_HOME=$HOME/.desmos
export DAEMON_NAME=desmos
export DAEMON_ALLOW_DOWNLOAD_BINARIES=true
export DAEMON_RESTART_AFTER_UPGRADE=true
export UNSAFE_SKIP_BACKUP=false

IMPORTANT: If you don't have much free disk space, please set UNSAFE_SKIP_BACKUP=true to avoid your node failing the upgrade due to insufficient disk space when creating the backup.

Once you're done, please reload the ~/.profile file by running

source ~/.profile

You can verify the values set by running

echo $DAEMON_NAME

If this outputs desmos you are ready to go.

3. Copying Desmos files in the proper folders

In order to work properly, Cosmovisor needs the desmos binary to be placed in the ~/.desmos/cosmovisor/genesis/bin folder. To do this you can simply run the following command:

mkdir -p ~/.desmos/cosmovisor/genesis/bin/
cp $(which desmos) ~/.desmos/cosmovisor/genesis/bin/

To verify that you have setup everything correctly, you can run the following command:

cosmovisor version

This should output the Desmos version.

4. Restarting your node

Finally, if you've setup everything correctly you can now restart your node. To do this you can simply stop the running desmos start and re-start your Desmos node using the following command:

cosmovisor start

Updating the service file

If you are running your node using a service, you need to update your service file to use cosmovisor instead of desmos. To do this you can simply run the following command:

sudo tee /etc/systemd/system/desmosd.service > /dev/null <<EOF  
[Unit]
Description=Desmos Full Node
After=network-online.target

[Service]
User=$USER
ExecStart=$(which cosmovisor) start
Restart=always
RestartSec=3
LimitNOFILE=4096

Environment="DAEMON_HOME=$HOME/.desmos"
Environment="DAEMON_NAME=desmos"
Environment="DAEMON_ALLOW_DOWNLOAD_BINARIES=true"
Environment="DAEMON_RESTART_AFTER_UPGRADE=true"
Environment="UNSAFE_SKIP_BACKUP=false"

[Install]
WantedBy=multi-user.target
EOF

IMPORTANT: If you don't have much free disk space, please set UNSAFE_SKIP_BACKUP=true to avoid your node failing the upgrade due to insufficient disk space when creating the backup.

Once you have edited your system file, you need to reload it using the following command:

sudo systemctl daemon-reload

Finally, you can restart is as follows:

sudo systemctl restart desmosd