MinerConnectionError when "helium-miner" container is unhealthy

[posterzh]

Follow up to:

• MinerConnectionError: Unable to connect to miner http://helium-miner:4467 #350

Thoughts:

• For any miner, if helium-miner container is unhealthy, then one of the following actions makes MinerConnectionError.
  • open the diagnostics page.
  • call diagnostics/json endpoint
  • upload the diagnostics to the Google big query

The unhealthy 'helium-miner container can be identified as follows:

1. Balena device summary looks good and all containers are running, but it's impossible to SSH into helium-miner.
   For example, https://dashboard.balena-cloud.com/devices/77a9b60b2ab317be68d0967843c53429
   

2. Balena device summary looks good and all containers are running, but SSH connection into helium-miner get dropped immediately.
   For example, https://dashboard.balena-cloud.com/devices/e2967d85a0a1dce2c92b2ff445354752
   

[posterzh]

The reason of this issue is most likely the corrupted EMMC and the following actions can fix:

• Purge the device
• Reflash the EMMC
• Replace the EMMC