Error establishing a database connection

You may want to take a look at our guide on troubleshooting memory and network issues. It doesn't have all the answers, since they'll vary from case to case, but it does provide some good starting points for diagnosing issues like this.

https://www.linode.com/docs/troubleshoo … ing-issues">https://www.linode.com/docs/troubleshooting/troubleshooting-memory-and-networking-issues

Since support noted that your Linode is OOMing, I'd focus on processes that might be consuming a great deal of RAM. If something looks like it's hogging all the resources, that's the first thing to add to your troubleshooting checklist. Certain software defaults to rather obnoxious settings that can cause excess resource consumption, but the configuration can usually be tuned to be less resource intensive.

I'd also recommend checking the available space in your Linode's disk image. MySQL will fail if it doesn't have enough disk space to maintain itself, which can cause the error that you're seeing. You can check your available space with the "df -h" command.