I have a Raspberry Pi 2B, I installed first Raspberry OS lite and then Ubuntu Server. The behavior I will descript was the same in both systems.
So, I wanted to use Docker to run a web server (1 compose with nginx, php, flask and python), samba server, ftp server (1 compose) and transmission (1 compose with transmission, transmission-rss and python). I installed it and all seemed good, everything run smoothly. Then after few hour, the raspberry it is unreachable. By ssh, sftp, the docker ports, nothing, I have to plug it off to force a reboot. I am not able to connect to it with a screen and a keyboard to check if it is blocked or it is only a network problem. It could happen after 6 or after 15, it happens every time but with different timing.
I looked at the syslog and it seems that for some reason when it happens, it is disabled the ipv4 interface of eth0. If you want to take a look here https://pastebin.com/7G1ARUNx you can find the syslogs of the last time it happened. I am sure it happened around 8.30 because I have a device that upload an image every minute and it stopped at that time.
If it matters, to the raspberry I have a 2.5" exfat hard disk connected to. I already discarded the electrical power problem trying without it or with an external powered case.
Anyone knows how can I fix this problem? Maybe it is because the pi 2 is old and it isn't powerful enough to run all this things, I don't know. At the moment I am running Ubuntu server. Thank you.