Automatic Node Upgrade: Nymvisor Setup and Usage

The Nymvisor binary was built in the building nym section. If you haven’t yet built Nym and want to run the code, go there first. You can build just Nymvisor with cargo build --release --bin nymvisor.

Any syntax in <> brackets is a user’s unique variable. Exchange with a corresponding name without the <> brackets.

What is Nymvisor?

Nymvisor is a process manager for Nym binaries that monitors the Nym release information for any newly released binaries. If it detects any changes, Nymvisor can automatically download the binary, stop the current binary, switch from the old binary to the new one, and finally restart the underlying process with the new binary.

In essence, it tries to mirror the behaviour of Cosmovisor, a tool used by Cosmos blockchain operators for managing/automating chain upgrades. Nymvisor, however, introduces some Nym-specific changes since, for example, upgrade information is obtained from our GitHub releases page instead of (in the case of Cosmos blockchains) governance proposals.

You can use Nymvisor to automate the upgrades of the following binaries:

  • nym-api
  • nym-mixnode
  • nym-gateway
  • nym-network-requester
  • nym-client
  • nym-socks5-client

Warning

Nymvisor is an early and experimental software. Users should use it at their own risk.

Current version

0.1.0

Preliminary steps

You need to have at least one Mixnet node / client / Nym API instance already set up on the same VPS that you wish to run Nymvisor on.

Using Nymvisor presumes your VPS is running an operating system that is compatible with the pre-compiled binaries avaliable on the Github releases page. If you’re not, then until we’re packaging for a greater variety of operating systems, you’re stuck with manually upgrading your node.

Setup and Usage

Viewing command help

You can check that your binaries are properly compiled with:

./nymvisor --help

Which should return a list of all available commands.

Console output

Usage: nymvisor [OPTIONS] <COMMAND>

Commands:
  init               Initialise a nymvisor instance with persistent Config.toml file
  run                Run the associated daemon with the preconfigured settings
  build-info         Show build information of this binary
  daemon-build-info  Show build information of the associated daemon
  add-upgrade        Queues up another upgrade for the associated daemon
  config             Show configuration options being used by this instance of nymvisor
  help               Print this message or the help of the given subcommand(s)

Options:
  -c, --config-env-file <CONFIG_ENV_FILE>
          Path pointing to an env file that configures the nymvisor and overrides any preconfigured values
  -h, --help
          Print help
  -V, --version
          Print version

You can also check the various arguments required for individual commands with:

./nymvisor <COMMAND> --help

Initialising your Nymvisor Instance

This example will use the Mix Node binary as an example - however replacing nym-mixnode with any other supported binary will work the same.

Initialise your Nymvisor instance with the following command. You must initialise Nymvisor with the binary you wish to add upgrades for:

./nymvisor init --daemon-home ~/.nym/<NODE_TYPE>/<NODE_ID> <PATH_TO_NODE_BINARY>

Where the value of --daemon-home might be ~/.nym/mixnodes/my-node and <PATH_TO_NODE_BINARY> might be /home/my_user/nym/target/release/nym-mixnode, or wherever your node binary is located.

Console output

2024-04-11T12:17:13.258984Z  INFO common/config/src/lib.rs:76: saving config file to /home/runner/.nym/nymvisors/instances/nym-mixnode-default/config/config.toml    

id:                                nym-mixnode-default
daemon name:                       nym-mixnode
daemon home:                       /home/runner/.nym/mixnodes/my-node
upstream base upgrade url:         https://nymtech.net/.wellknown/
disable nymvisor logs:             false
CUSTOM upgrade data directory      ""
upstream absolute upgrade url:     ""
allow binaries download:           true
enforce download checksum:         true
restart after upgrade:             true
restart on failure:                false
on failure restart delay:          10s
max startup failures:              10
startup period duration:           2m
shutdown grace period:             10s
CUSTOM backup data directory       ""
UNSAFE skip backups                false

By default this will create config files at ~/.nym/nymvisors/instances/<NODE_TYPE>-default/config/config.toml as shown in the console output above. For config options look at the different --flags available, or the environment variables section below.

Running your Nymvisor Instance

Nymvisor acts as a wrapper around the specified node process - it has to do this in order to be able to pause and restart this process. As such, you need to run your node via Nymvisor!

The interface to the nymvisor run <ARGS> command is quite simple. Any argument passed after the run command will be passed directly to the underlying daemon, for example: nymvisor run run --id my-mixnode will run the $DAEMON_NAME run --id my-mixnode command (where DAEMON_NAME is the name of the binary itself (e.g. nym-api, nym-mixnode, etc.)).

run Nymvisor and start your node via the following command. Make sure to stop any existing node before running this command.

./nymvisor run run --id <NODE_ID>

Console output

2024-04-11T12:17:13.262203Z  INFO tools/nymvisor/src/cli/run.rs:31: starting nymvisor for nym-mixnode
2024-04-11T12:17:13.262748Z  INFO get_build_information: tools/nymvisor/src/daemon/mod.rs:63: attempting to obtain daemon build information self.executable_path="/home/runner/.nym/nymvisors/data/nym-mixnode/current/bin/nym-mixnode"
2024-04-11T12:17:13.265290Z  INFO tools/nymvisor/src/tasks/launcher/mod.rs:115: checking changes in the upgrade plan file...
2024-04-11T12:17:13.267630Z  WARN tools/nymvisor/src/tasks/launcher/mod.rs:174: the daemon has terminated by itself - was it a short lived command?
2024-04-11T12:17:13.267640Z  INFO tools/nymvisor/src/tasks/launcher/mod.rs:176: it finished with the following exit status: exit status: 1
2024-04-11T12:17:13.267645Z  INFO tools/nymvisor/src/tasks/launcher/mod.rs:42: the daemon has run for 5ms 316us 564ns
2024-04-11T12:17:13.267650Z  INFO tools/nymvisor/src/cli/run.rs:57: the daemon has finished execution
2024-04-11T12:17:13.267683Z  INFO tools/nymvisor/src/cli/run.rs:77: Upgrade plan watcher has finished execution
2024-04-11T12:17:13.267688Z  INFO tools/nymvisor/src/cli/run.rs:77: Upstream poller has finished execution

Nymvisor will now manage your node process (for an in-depth overview of this command check the in-depth command information below). It will periodically poll this endpoint (replace nym-mixnode with whatever node you may actually be running via Nymvisor) and check for a new version of the binary it is watching. If this exists, it will then, using the information there:

  • pause your node process
  • grab the new binary (version)
  • verify it against the provided checksum
  • perform a data backup of the existing node
  • replace the old binary with the new one
  • restart the process

And that’s it! Check the maintenance page for information on Nymvisor process maintenance and automation, and you can find more in-depth information about the various aspects of Nymvisor such as what happens under the hood for various commands.

Creating an Adhoc Upgrade

nymvisor add-upgrade <PATH_TO_EXECUTABLE> --upgrade-name=<NAME> --arg1=value1 --arg2=value2 ... can be used to amend an existing upgrade-plan.json by creating new entries or to add an executable to an existing scheduled upgrade so that it would not have to be downloaded.

Generally users will not have to use this command. Situations in which this command might be used are:

  • an adhoc upgrade if e.g. a patched version of a binary was required
  • if a user doesn’t trust the verification process of Nymvisor’s pipeline and wishes to build/verify the binary themselves before using Nymvisor to perform the upgrade
  • if a user isn’t using a currently supported operating system and needs to manually specify a binary they have built themselves

Similarly to init, add-upgrade requires a positional argument specifying a valid path to the upgrade binary. Furthermore, the --upgrade-name keyword argument must be set in order to declare the upgrade name. The remaining arguments are optional. They include:

  • --force - if specified, will allow Nymvisor to overwrite existing upgrade binary / upgrade-info.json files if they already exist
  • --add-binary - indicate that this command should only add binary to an existing scheduled upgrade
  • --now - if specified will force the upgrade to be performed immediately (technically not ‘immediately’ within few seconds). It can’t be specified alongside either --upgrade-time or --upgrade-delay arguments
  • --publish-date - if a new upgrade-info.json file is going to be created, this argument will specify the publish_date metadata field. Otherwise, the current time will be used. The RFC3339 datetime format is expected
  • --upgrade-time - specifies the time at which the provided upgrade will be performed (RFC3339 formatted). If left unset, the upgrade will be performed in 15 minutes. It can’t be specified alongside either --now or --upgrade-delay arguments.
  • --upgrade-delay - specifies delay until the provided upgrade is going to get performed. If let unset, the upgrade will be performed in 15 minutes. It can’t be specified alongside either --upgrade_time or --now arguments.

Config

The output format of nymvisor config can be further configured with --output argument. By default a human-readable text representation is used:

id:                                nym-mixnode-default
daemon name:                       nym-mixnode
daemon home:                       /home/nym/.nym/mixnodes/my-mixnode
upstream base upgrade url:         https://nymtech.net/.wellknown/
disable nymvisor logs:             false
CUSTOM upgrade data directory      ""
upstream absolute upgrade url:     ""
allow binaries download:           true
enforce download checksum:         true
restart after upgrade:             true
restart on failure:                false
on failure restart delay:          10s
max startup failures:              10
startup period duration:           2m
shutdown grace period:             10s
CUSTOM backup data directory       ""
UNSAFE skip backups                false

Adding --output=json would format the same data into JSON which can be more easily parsed programmatically to e.g. pipe the output into jq for further processing.

nymvisor config --output=json

outputs:

{"nymvisor":{"id":"nym-mixnode-default","upstream_base_upgrade_url":"https://nymtech.net/.wellknown/","upstream_polling_rate":"1h","disable_logs":false,"upgrade_data_directory":null},"daemon":{"name":"nym-mixnode","home":"/home/nym/.nym/mixnodes/my-mixnode","absolute_upstream_upgrade_url":null,"allow_binaries_download":true,"enforce_download_checksum":true,"restart_after_upgrade":true,"restart_on_failure":false,"failure_restart_delay":"10s","max_startup_failures":10,"startup_period_duration":"2m","shutdown_grace_period":"10s","backup_data_directory":null,"unsafe_skip_backup":false}}

CLI Overview

Command options are:

  • help, --help, or -h - Output Nymvisor help information and display the available commands.
  • config - Display the current Nymvisor configuration, that means displaying the current configuration file that might have been overridden with environment variables value that Nymvisor is using.
  • init - Generate a config.toml file for this instance of Nymvisor that will use the provided arguments alongside any environmental variables that are set.
  • add-upgrade - Add an upgrade manually to Nymvisor. This command allows you to easily add the binary corresponding to an upgrade or amend the existing upgrade-plan.json whilst creating new upgrade-info.json file.
  • build-info - Output the build information.
  • daemon-build-info - Output the build information of the current binary used by the associated daemon.
  • run - Run the configured binary using the rest of the provided arguments.
  • -V or --version - Output the Nymvisor version

Similarly to other Nym binaries, Nymvisor supports a global --config-env-file or -c flag that allows specifying path to a .env file defining any relevant environmental variables that are going to be applied to any of the Nymvisor commands as described in the Environment section.

For commands that depend on Nymvisor config file (i.e. all but init), the configuration file is loaded as follows:

  • if available, reading $NYMVISOR_CONFIG_PATH
  • otherwise, if $NYMVISOR_ID is set, a default path will be used, i.e. $HOME/.nym/nymvisors/instances/$NYMVISOR_ID/config/config.toml
  • finally, if there’s only a single nymvisor instance instantiated (as defined by directories in $HOME/.nym/nymvisors/instances), that one will be loaded
  • if all of the above fails, an error is returned

Nymvisor attempts to load the file from the derived path. If it fails, it attempts to use one of the older schemas to and upgrade it as it goes, the loaded configuration is then overridden with any value that might have been set in the environment.

Environment Variables

Please note environmental variables take precedence over any arguments passed, i.e. if one were to specify --daemon_home="/foo" and set DAEMON_HOME="bar", the value of "bar" would end up being used.

For any of its commands as described in CLI Overview section, Nymvisor reads its configuration from the following environment variables:

  • NYMVISOR_ID is the human-readable identifier of the particular Nymvisor instance.
  • NYMVISOR_CONFIG_PATH is used to manually override path to the configuration file of the Nymvisor instance.
  • NYMVISOR_UPSTREAM_BASE_UPGRADE_URL (defaults to https://nymtech.net/.wellknown/) is the base url of the upstream source for obtaining upgrade information for the daemon. It will be used fo constructing the full url, i.e. $NYMVISOR_UPSTREAM_BASE_UPGRADE_URL/$DAEMON_NAME/upgrade-info.json.
  • NYMVISOR_UPSTREAM_POLLING_RATE (defaults to 1h) is polling rate the upstream url for upgrade information.
  • NYMVISOR_DISABLE_LOGS (defaults to false). If set to true, this will disable Nymvisor logs (but not the underlying process) completely.
  • NYMVISOR_UPGRADE_DATA_DIRECTORY is the custom directory for upgrade data - binaries and upgrade plans. If not set, the global Nymvisors’ data directory will be used instead.
  • DAEMON_NAME is the name of the binary itself (e.g. nym-api, nym-mixnode, etc.).
  • DAEMON_HOME is the location where the nymvisor/ directory is kept that contains the auxiliary files associated with the underlying daemon instance, such as any backups or current version information, e.g. $HOME/.nym/nym-api/my-nym-api, $HOME/.nym/mixnodes/my-mixnode, etc.
  • DAEMON_ABSOLUTE_UPSTREAM_UPGRADE_URL is the absolute (i.e. the full url) upstream source for upgrade plans for this daemon. The url has to point to an endpoint containing a valid UpgradeInfo json file. If set it takes precedence over NYMVISOR_UPSTREAM_BASE_UPGRADE_URL.
  • DAEMON_ALLOW_BINARIES_DOWNLOAD (defaults to true), if set to true, it will enable auto-downloading of new binaries (as declared by urls in corresponding upgrade-info.json files). For security reasons one might wish to disable it and instead manually provide binaries by either placing them in the appropriate directory or by invoking add-upgrade command.
  • DAEMON_ENFORCE_DOWNLOAD_CHECKSUM (defaults to true), if set to true Nymvisor will require that a checksum is provided in the upgrade plan for the upgrade binary to be downloaded. If disabled, Nymvisor will not require a checksum to be provided, but still check the checksum if one is provided.
  • DAEMON_RESTART_AFTER_UPGRADE (defaults to true), if set to true Nymvisor will restart the subprocess with the same command-line arguments and flags (but with the new binary) after a successful upgrade. Otherwise (false), Nymvisor stops running after an upgrade and requires the system administrator to manually restart it. Note restart is only after the upgrade and does not auto-restart the subprocess after an error occurs. That is controlled via DAEMON_RESTART_ON_FAILURE.
  • DAEMON_RESTART_ON_FAILURE (defaults to true), if set to true, Nymvisor will restart the subprocess with the same command-line arguments and flags if it has terminated with a non-zero exit code.
  • DAEMON_FAILURE_RESTART_DELAY (defaults to 10s), if DAEMON_RESTART_ON_FAILURE is set to true, this will specify a delay between the process shutdown (with a non-zero exit code) and it being restarted.
  • DAEMON_MAX_STARTUP_FAILURES (defaults to 10) if DAEMON_RESTART_ON_FAILURE is set to true, this defines the maximum number of startup failures the subprocess can experience in a quick succession before no further restarts will be attempted and Nymvisor will terminate.
  • DAEMON_STARTUP_PERIOD_DURATION (defaults to 120s) if DAEMON_RESTART_ON_FAILURE is set to true, this defines the length of time during which the subprocess is still considered to be in the startup phase when its failures are going to be counted towards the limit defined in DAEMON_MAX_STARTUP_FAILURES.
  • DAEMON_SHUTDOWN_GRACE_PERIOD (defaults to 10s), specifies the amount of time Nymvisor is willing to wait for the subprocess to undergo graceful shutdown after receiving an interrupt before it sends a kill signal.
  • DAEMON_BACKUP_DATA_DIRECTORY specifies custom backup directory for daemon data. If not set, DAEMON_HOME/nymvisor/backups is used instead.
  • DAEMON_UNSAFE_SKIP_BACKUP (defaults to false), if set to true, all upgrades will be performed directly without performing any backups. Otherwise (false), Nymvisor will back up the contents of DAEMON_HOME before trying the upgrade.

Dir structure

The folder structure of Nymvisor is heavily inspired by Cosmovisor, but with some notable changes to accommodate our binaries having possibly multiple instances due to their different --id flags. The data is spread through three main directories:

  • in a global nymvisors data directory shared by all Nymvisor instances (default: $HOME/.nym/nymvisors/data) that contains daemon upgrade plans, binaries and upgrades histories. It includes a subdirectory for each version of the application (i.e. genesis or upgrades<name>). Within each subdirectory is the application binary (i.e. bin/$DAEMON_NAME), the associated upgrade-info.json and any additional auxiliary files associated with each binary. current is a symbolic link to the currently active directory (i.e. genesis or upgrades/<NAME>)
  • in a home directory of a particular nymvisor instance (e.g. $HOME/.nym/nymvisors/instances/<nymvisor-instance-id>/). It includes subdirectories for its configuration file (i.e. config/config.toml), that preconfigures the instance, and for any additional persistent data that might be added in the future (i.e. data)
  • in a nymvisor data directory inside the home directory of the managed daemon instance (default: $HOME/.nym/$DAEMON_NAME/nymvisor) that contains subdirectories for data backups (i.e. backups/<name>) and current version information (current-version-info.json)

A sample full structure looks as follows:

~/.nym
├── nymvisors
│   ├── instances
│   │   ├── <id1>
│   │   │   ├── config
│   │   │   │   └── config.toml
│   │   │   └── data
│   │   │       └── ...
│   │   └── <id2>
│   │       └── ...
│   └── data
│       ├── nym-api
│       │   ├── current -> genesis or upgrades/<name>
│       │   ├── genesis
│       │   │   ├── bin
│       │   │   │   └── nym-api
│       │   │   └── upgrade-info.json
│       │   ├── upgrades
│       │   │   └── <upgrade-name>
│       │   │       ├── bin
│       │   │       │   └── nym-api
│       │   │       └── upgrade-info.json
│       │   ├── upgrade-history.json
│       │   └── upgrade-plan.json
│       ├── nym-mixnode
│       │   └── ...
│       └── $DAEMON_NAME
│           └── ...
└── nym-api
├── <id1>
│   ├── config
│   │   └── <nym-api-config-data>
│   ├── data
│   │   └── <nym-api-data>
│   └── nymvisor
│       ├── backups
│       │   └── <upgrade-name>
│       │       └── ....
│       └── current-version-info.json
└── <id2>
└── ...

Commands In-Depth

This section outlines what happens under the hood with the following commands:

Init

init does the following:

  • executes the $DAEMON_NAME build-info command on the daemon executable to check its validity and obtain its name
  • creates the required directory structure:
    • $DAEMON_HOME/nymvisor folder if it doesn’t yet exist
    • $DAEMON_BACKUP_DATA_DIRECTORY folder if it doesn’t yet exist
    • $NYMVISOR_UPGRADE_DATA_DIRECTORY folder if it doesn’t yet exist
    • $NYMVISOR_UPGRADE_DATA_DIRECTORY/$DAEMON_NAME/genesis/bin folder if it doesn’t yet exist
    • $NYMVISOR_UPGRADE_DATA_DIRECTORY/$DAEMON_NAME/upgrades folder if it doesn’t yet exist
  • copies the provided executable to $NYMVISOR_UPGRADE_DATA_DIRECTORY/$DAEMON_NAME/genesis/bin/$DAEMON_NAME
  • generates initial $NYMVISOR_UPGRADE_DATA_DIRECTORY/$DAEMON_NAME/genesis/upgrade-info.json file based on the provided binary
  • generates initial $DAEMON_HOME/nymvisor/current-version-info.json file based on the provided binary
  • creates a $NYMVISOR_UPGRADE_DATA_DIRECTORY/$DAEMON_NAME/current symlink pointing to $NYMVISOR_UPGRADE_DATA_DIRECTORY/$DAEMON_NAME/genesis
  • saves the Nymvisor instance’s config file to $NYMVISOR_CONFIG_PATH and creates the full directory structure for the file
  • outputs (to stdout) the full configuration used

nymvisor init is specifically for initializing Nymvisor, and should not be confused with a daemon’s init command - such as nym-mixnode init (e.g. cosmovisor run init).

Run

nymvisor run is a lightweight wrapper around the underlying daemon. It uses only a single thread and spawns three simple tasks:

  • an upstream poller that checks the upstream source (as defined by DAEMON_ABSOLUTE_UPSTREAM_UPGRADE_URL or derived from NYMVISOR_UPSTREAM_BASE_UPGRADE_URL) for any recently released upgrades. It then creates appropriate upgrade-info.json file and updates the upgrade-plan.json
  • a file watcher for the upgrade-plan.json file that can notify the main run loop of upgrades that were added by either the above upstream poller task or via the add-upgrade command,
  • the daemon run loop that:
    • runs the DAEMON_NAME with the provided arguments until:
      • it completes the execution (with any exit code),
      • Nymvisor receives a SIGINT, SIGTERM or SIGQUIT,
      • a new upgrade is scheduled to be performed (by other task watching for changes in upgrade-plan.json and waiting until the upgrade_time,
    • if DAEMON_UNSAFE_SKIP_BACKUP is not set to true, it backups the content of DAEMON_HOME directory,
    • performs the binary upgrade by:
      • creating a temporary, exclusive and non-blocking, upgrade.lock file for the DAEMON_NAME. flock with LOCK_EX | LOCK_NB is used for that purpose. The file is created in case users didn’t read any warnings and attempted to run multiple instances of nymvisor managing the same DAEMON_NAME,
      • downloading the upgrade binary for the runners architecture using one of the urls defined in upgrade-info.json. Note, however, that this is only done if the binary associated with the <UPGRADE-NAME> does not already exist and DAEMON_ALLOW_DOWNLOAD_BINARIES is set to true,
        • if the binary has been downloaded and DAEMON_ENFORCE_DOWNLOAD_CHECKSUM is set to true, the file checksum is verified using the specified algorithm,
      • verifying the upgrade binary - checking if it’s a valid executable with expected build-info. Note that this will also set a+x bits on the file if those permissions have not already been set,
        • removing the queued upgrade from upgrade-plan.json,
        • inserting new upgrade into the upgrade-history.json,
        • updating the current-version-info.json,
        • updating the $NYMVISOR_UPGRADE_DATA_DIRECTORY/$DAEMON_NAME/current symlink to the upgrade directory,
        • removing the upgrade.lock file.
    • the above loop is repeated if either:
      • the daemon has crashed and DAEMON_MAX_STARTUP_FAILURES has not been reached yet,
      • the daemon has successfully been upgraded, DAEMON_RESTART_AFTER_UPGRADE has been set to true and the manual flag on the performed upgrade has been set to false.

Add-Upgrade

nymvisor add-upgrade does the following:

  • executes the $DAEMON_NAME build-info command on the daemon executable to check its validity and obtain its name
  • attempts to load existing upgrade-info.json for the provided <upgrade-name>. If it already exists and neither --force nor --add-binary was specified, Nymvisor will terminate
  • checks if upgrades/<upgrade-name>/$DAEMON_NAME binary already exists. If it does and --force flag was not specified, Nymvisor will terminate the provided upgrade binary is copied to its appropriate location
  • if applicable, new upgrade-info.json is created and written to its appropriate location
  • upgrade-plan.json is updated with the new upgrade details. If there’s an active Nymvisor instance running, this change will be detected to initialise upgrade process
Last change: 2024-04-11, commit: f978552