Ubuntu – Shell script works when run manually but does not when run at docker container startup

I installed Docker on a Synology NAS.
I created a container that runs an ubuntu that runs a website server.

To launch my service (named "dodoc"), I use npm and pm2.

So when my container start, I have to manually open the container terminal and run the following commands :

cd /home
pm2 start dodoc
pm2 startup

And then, it works perfectly.

The problem is that I would like to launch automatically the service at container startup. Usually, a pm2 save should do it. But on a Synology NAS it does not work, don’t know why.

So… I tried a different approach :
using a shell script as a CMD on my container.

so my container CMD line is :

/bin/bash -c /root/Documents/startupCommands.sh

Like this, my container does run my script at startup, but the script does not work whereas it works if I run it manually through the terminal.

The script (named "startupCommands.sh") :

#!/bin/bash

cd /home && pm2 start dodoc
cd /home && pm2 startup

/bin/bash

On a NAS Synology, we have to set a directory on the NAS where the container will have access.
This directory, where I can put my script file is at /root/Documents in the container terminal.
But, my service is to be run at /home.
Why did I put my script in a different directory ? Because on a Synology NAS, you have to set the CMD line at container creation and can’t modify it after. So if you try to run a script.sh that does not exist yet, the container will keep reboot indefinitely. So you have to put the script file in a directory you have access without using container terminal.

Well… if I manually do the following command in the Terminal, it works :

root@ubuntu-dodoc10:/home# /root/Documents/startupCommands.sh
[PM2] Spawning PM2 daemon with pm2_home=/root/.pm2
[PM2] PM2 Successfully daemonized
[PM2] Starting /home/dodoc in fork_mode (1 instance)
[PM2] Done.

But, if I give a look at the container log, that’s what happen at startup :

]0;root@ubuntu-dodoc10: /homeroot@ubuntu-dodoc10:/home# 
/root/Documents/startupCommands.sh: line 4: pm2: command not found
/root/Documents/startupCommands.sh: line 5: pm2: command not found

And obviously, the serveur does not start…

I’ve tried :

1. to install npm is the root directory
2. to use (cd /home && pm2 start dodoc) commands in the script
3. to create another script in the /home directory and run it from the first script

Nothing worked :'(

"Dokerfile" :

{
   "CapAdd" : null,
   "CapDrop" : null,
   "cmd" : "/bin/bash -c /root/Documents/startupCommands.sh",
   "cpu_priority" : 50,
   "enable_publish_all_ports" : false,
   "enable_restart_policy" : true,
   "enable_service_portal" : null,
   "enabled" : true,
   "env_variables" : [
      {
         "key" : "PATH",
         "value" : "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
      }
   ],
   "exporting" : false,
   "id" : "4fc2468eaf2a84c57ddb25f1818cdef6650a792d67ac6ad7d5d69e8fd470f8c0",
   "image" : "ubuntu:latest",
   "is_ddsm" : false,
   "is_package" : false,
   "links" : [],
   "memory_limit" : 1073741824,
   "name" : "ubuntu-dodoc-test",
   "network" : [
      {
         "driver" : "host",
         "name" : "host"
      }
   ],
   "network_mode" : "host",
   "port_bindings" : [],
   "privileged" : false,
   "shortcut" : {
      "enable_shortcut" : false,
      "enable_status_page" : false,
      "enable_web_page" : false,
      "web_page_url" : ""
   },
   "use_host_network" : true,
   "volume_bindings" : [
      {
         "host_volume_file" : "/docker/dodoc",
         "mount_point" : "/root/Documents",
         "type" : "rw"
      }
   ]
}