How will logging work?
pm2 logs stdout and stderr into $HOME/.pm2/logs. This can be custom at the app level (details here). While pm2 supports basic features like log rotation, I for one favour log4js-node. In that case note the doc on clustering.
::: warning Caveat At point of writing I have not tested clustered logging myself. Documentation seems fairly straightforward. It should work... :::
How will code deployment look like?
Step 1: enable password-less SSH to remote hosts
pm2 expects to deploy over ssh. Have remote hosts trust the deploying host by sharing keys:
%ssh-keygen -t rsa
# on FreeBSD ssh-copy-id does not seem to default to ~/.ssh/id_rsa.pub so we have to be explicit
%ssh-copy-id -i ~/.ssh/id_rsa.pub userid@remote.host
Validate password-less SSH
%ssh userid@remote.host
Step 2: configure ecosystem.config.js
I was stuck for some time wondering why I kept getting 'unexpected token -' error. It would have been obvious for a seasoned JS dev, and eventually I figured hash keys with hyphens need to be enclosed with quotes. Here's a simple working config used.
module.exports = {
apps: [{
name: 'testinstance',
script: 'testinstance.js'
}],
deploy: {
production: {
user:'userid',
host:['prodhost.domain.com'],
ssh_options: 'StrictHostKeyChecking=no',
ref: 'origin/master',
repo: 'https://github.com/jhfoo/testpm2.git',
path:'/home/userid/prod',
'pre-setup': '',
'post-setup': 'ls -l',
'pre-deploy-local': "echo 'This is a local executed command'",
'post-deploy': 'npm install'
}
}
}
Step 3: Setup and Deploy
Documentation is a bit sparse on the PM2 web site. Here's my understanding of the difference in the two:
Setup is a one-time call to configure the remote host 'environment'. By that I mean:
- Creating directories
- Setting up and downloadiung Git repo
The above 2 are automatically done for you per your 'repo' and 'path' entries. You can always include scripts to be run before and after setup.
%pm2 deploy ecosystem.config.js production setup --force
Deploy does the following:
- Execute pre-deploy script 'pre-deploy-local'
- Pull the latest from repo
- Execute post-deploy script 'post-deploy'
::: warning Question How does pm2 handle rollbacks?pm :::