Process File

Process File

PM2 empowers your process management workflow. It allows you to fine-tune the behavior, options, environment variables, logs files of each application via a process file. It’s particularly useful for micro-service based applications.

Configuration format supported are Javascript, JSON and YAML.

Generate configuration

To generate a sample process file you can type this command:

pm2 ecosystem

This will generate a sample, ecosystem.config.js.

To generate a ecosystem file without any comment just run pm2 ecosystem simple.

Javascript format

module.exports = {
  apps : [{
    name        : "worker",
    script      : "./worker.js",
    watch       : true,
    env: {
      "NODE_ENV": "development",
    },
    env_production : {
       "NODE_ENV": "production"
    }
  },{
    name       : "api-app",
    script     : "./api.js",
    instances  : 4,
    exec_mode  : "cluster"
  }]
}

Note that using a Javascript configuration file requires to end the file name with .config.js

JSON format

The configuration can also be in JSON format.

{
  "apps" : [{
    "name"        : "worker",
    "script"      : "./worker.js",
    "watch"       : true,
    "env": {
      "NODE_ENV": "development"
    },
    "env_production" : {
       "NODE_ENV": "production"
    }
  },{
    "name"       : "api-app",
    "script"     : "./api.js",
    "instances"  : 4,
    "exec_mode"  : "cluster"
  }]
}

JSON5 format

Alternatively, JSON5 is also supported

{
  apps: [{
    name: 'worker',
    script: './worker.js',
    watch: true,
    env: {
      NODE_ENV: 'development'
    },
    env_production: {
      NODE_ENV: 'production'
    }
  }, {
    name: 'api-app',
    script: './api.js',
    instances: 4,
    exec_mode: 'cluster'
  }]
}

YAML format

Here is the same example in YAML format (use JSON format if possible):

apps:
  - script   : ./api.js
    name     : 'api-app'
    instances: 4
    exec_mode: cluster
  - script : ./worker.js
    name   : 'worker'
    watch  : true
    env    :
      NODE_ENV: development
    env_production:
      NODE_ENV: production

CLI

Then you can run and manage your processes easily:

# Start all applications
pm2 start ecosystem.config.js

# Start only the app named worker-app
pm2 start ecosystem.config.js --only worker-app

# Stop all
pm2 stop ecosystem.config.js

# Restart all
pm2 start   ecosystem.config.js
## Or
pm2 restart ecosystem.config.js

# Reload all
pm2 reload ecosystem.config.js

# Delete all
pm2 delete ecosystem.config.js

Act on a specific process

You can also act on a particular application by using its name and the option --only <app_name>:

pm2 start   ecosystem.config.js --only api-app
pm2 restart ecosystem.config.js --only api-app
pm2 reload  ecosystem.config.js --only api-app
pm2 delete  ecosystem.config.js --only api-app

Updating running conf

Starting PM2 v2.1.X, environments are immutable by default, that means the environment will never be updated unless you tell PM2 to do so, to update configurations, you will need to use --update-env options. Please note that some options will not be updated (options that are listed under General Attributes below). More documentation on –update-env here

Example:

pm2 restart ecosystem.config.js --update-env
pm2 startOrReload ecosystem.config.js --update-env

Switching environments

You may have noticed that you can declare environment-specific variables with the attribute env_* (e.g. env_production, env_staging…). They can be switched easily. You just need to specify the --env <environment_name> when acting on the application declaration.

Example:

# Inject what is declared in env_production
pm2 start process.json --env production

# Inject what is declared in env_staging
pm2 restart process.json --env staging

Attributes available

Application behavior and configuration can be fine-tuned with the following attributes:

General

Advanced features

Log files

Control flow

Considerations

All command line options passed when using the JSON app declaration will be dropped i.e.

Multiple JSON

You can start as many JSON application declarations as you want.

cat node-app-1.json

{
  "name" : "node-app-1",
  "script" : "app.js",
  "cwd" : "/srv/node-app-1/current"
}

pm2 start node-app-2.json
ps aux | grep node-app
root  14735  5.8  1.1  752476  83932 ? Sl 00:08 0:00 pm2: node-app-1
root  24271  0.0  0.3  696428  24208 ? Sl 17:36 0:00 pm2: node-app-2

Note that if you execute pm2 start node-app-2 again, it will spawn an additional instance node-app-2.

CWD

cwd: your JSON declaration does not need to reside with your script. If you wish to maintain the JSON(s) in a location other than your script (say, /etc/pm2/conf.d/node-app.json) you will need to use the cwd feature (Note, this can be really helpful for capistrano style directory structures that uses symlinks). Files can be either relative to the cwd directory, or absolute (see example below).

CLI/JSON options

All the keys can be used in a JSON configured file, but will remain almost the same on the command line e.g.:

exec_mode         -> --execute-command
max_restarts      -> --max-restarts
force             -> --force

Using quotes to make an ESC, e.g.:

$pm2 start test.js --node-args "port=3001 sitename='first pm2 app'"

The nodeArgs argument will be parsed as

[
  "port=3001",
  "sitename=first pm2 app"
]

but not

[
  "port=3001",
  "sitename='first",
  "pm2",
  "app'"
]

Disabling logs

You can pass /dev/null to error_file or out_file to disable logs saving. Note : starting PM2 2.4.0, /dev/null or NULL disable logs independently of the platform.

Logs suffix

You can disable automatic ID suffixs on logs (e.g. app-name-ID.log) by passing enabling the option merge_logs: true

Environment definition

You’ll need to use --env <envname> to tell pm2 to use specific environment defined inside a process file :

{
  "apps" : [{
    "name"        : "worker",
    "script"      : "./worker.js",
    "watch"       : true,
    "env": {
      "NODE_ENV": "development"
    },
    "env_production" : {
       "NODE_ENV": "production"
    }
  },{
    "name"       : "api-app",
    "script"     : "./api.js",
    "instances"  : 4,
    "exec_mode"  : "cluster"
  }]
}

In this example, you will run pm2 start ecosystem.json and it will start your application with the default environment (in development so). Then you use pm2 start ecosystem.json --env production and it will use the attribute env_<name> where name is production here, so it will start your app with NODE_ENV=production.

Special ext_type

• min_uptime Value of min_uptime can be:
  • Number e.g. "min_uptime": 3000 means 3000 milliseconds.
  • String Therefore, we are making it short and easy to configure: h, m and s, e.g.: "min_uptime": "1h" means one hour, "min_uptime": "5m" means five minutes and "min_uptime": "10s" means ten seconds (those will be transformed into milliseconds).
• max_memory_restart Value of max_memory_restart can be:
  • Number e.g. "max_memory_restart": 1024 means 1024 bytes (NOT BITS).
  • String Therefore, we are making it short and easy to configure: G, M and K, e.g.: "max_memory_restart": "1G" means one gigabyte, "max_memory_restart": "5M" means five megabytes and "max_memory_restart": "10K" means ten kilobytes (those will be transformed into byte(s)).

• Optional values For example exec_mode can take cluster (cluster_mode) or fork (fork_mode) as possible values.

• Things to know
  • "instances": 0 means that PM2 will launch the maximum processes possible according to the numbers of CPUs (cluster mode)
  • array args, node_args and ignore_watch could be type of Array (e.g.: "args": ["--toto=heya coco", "-d", "1"]) or string (e.g.: "args": "--to='heya coco' -d 1")