Master Service Issues

The Master Service

One of two critical services that run on your hosted server, the "Master" service is in constant communication with your BATMs. All transactions & events use this channel.

See also:

CAS exposes port 7741, and your BATM (when properly configured) does everything through CAS. If the Master service is disrupted, your BATMs will fail to connect. They will all be offline.


All your BATMs report "Server Unreachable".

The underlying cause of this type problem may arise in any of five areas:

This article addresses common CAS issues.

If only one BATM is experiencing this symptom - and you operate multiple BATMs, please refer to this article instead:


First, identify if the Master service is running.

  1. Login to your remote server.

  2. From your server's command line interface (CLI), type:

  • sudo /batm/batm-manage info

Investigate the log:

If you can access the CAS GUI, you can view it there:        

  • Navigate to: Log Viewer/Master Log

  • Click on "GO TO END OF FILE".

  • Look for errors. Try to reproduce the error, then refresh the log.

  • The Master Log contains communication notes between your server and BATMs and contains a great deal of troubleshooting information.

If you cannot access the CAS GUI:

Start the master service using this special command:

sudo /batm/batm-manage fg master
  • the master service will attempt to start - but it will display ALL messages onscreen - successes AND failures. Not all failures are unexpected or unwanted; they are merely reporting tools and the information is used for complex debugging.

  • Errors reported towards the end are the most relevant.

If the master service is started without the “fg" switch (using “start"), then the master log will be concatenated to any previous master log, and can be examined by typing:

sudo cat /var/log/batm/master.log

Finally, create a support ticket & submit the server logs for further investigation if you’re unable to decipher the mystery yourself.

Check your buy & sell rate sources:

The Master service may shut down if it is unable to communicate with your rate provider. This is for your protection - to prevent sales & purchases that may be considerably askew from actual current prices. Always check that your rate provider is reliable and functioning. This shutdown may occur intermittently!


Ubuntu should be updated regularly, and it will need to be restarted occasionally. This is easy to overlook. If the Master service is suddenly giving you trouble, update Ubuntu and reboot your server.

Check that you have enough free space on your drive:

  • Should report at least 5gb free for the Master service to run reliably.

Ensure that any server firewalls expose the proper ports:

Is your CPU or memory overloaded? Run:

  • If the CPU or memory of any individual process exceeds 50%, you may need to increase your system specifications.

  • Usage surges (of either type) may result in random intermittent server reboots.

  • Memory depletion may result in the unpredictable termination of processes (killed).

Do you have a swap file?

Digital Ocean droplets do not have a swap file (by default).

A swap file is used by Linux to move memory to the file system when cramped. Linux (and more especially MySQL) uses A LOT or memory, and in fact MySQL will use all available permitted memory. Even if you increase your RAM to 256GB, MySQL may use almost all of it - resulting in continued occasional crashes. The solution is a swap file. Check to see if you have one in place with:

Create a swap file if none exists (if you see this):

To create a 2GB swap file (any size > 1GB on a 8GB system should suffice):

To make the change permanent, edit the /etc/fstab file and append /swapfile swap swap sw 0 0 to it:

  • Press Ctrl+X and “Y” to save and exit the editor.

The swap file should already be active, but verify with:

  • the swap file should now show a number greater than zero.

  • it should still show even after rebooting your system.

Other potential causes include:

  • Hardware failure,

  • Bandwidth limitations (each BATM may consume up to 4gb/mo),

  • Attacks by malicious actors overloading your server,

  • JAVA version mismatch. Installing extra software on your server may cause your server's JAVA be switched to a different, incompatible version. YOUR SERVER SHOULD BE DEDICATED TO CAS!

These problems are outside the scope of General Bytes support. Please contact your hosting provider or a third-party trusted vendor to address server issues and/or required upgrades. Watch your server usage graphs (if available). Use the "top" utility to watch processor load. It should stay well below 50% on a normal system.

If you've covered these steps and still have problems, create a support ticket.

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