Hi, we are currently in the process of testing a cluster of ubuntu 16.04 VM´s running ISPC 3.1.12. Our current setup is a webserver and a mirror server. Mail and DB server are separate. We do not run DNS in ISPC. There is one issue that I would be grateful to get the experienced opinion of you guys in here: how is ISPC behaving regarding custom cron jobs in a clustered situation. Lets say a payment system checks a database for a flag if something is payed, if not it will charge the stored credit card and wait for confirmation until then the flag will still say unpaid. Meanwhile the second server also running the same cron since it is a mirror and thus will do everything the main server is doing as well afaik. Now the second server will see the payment as still pending as well and also charge the same credit card. How can we prevent such a situation. TLDR: Will any non idempotent process that is executed via a cron job (regardless if it does manipulate a filesystem or a database) be a candidate for problems in a ISPC Mirror setup?
You can e.g. disable the crin on jailed cron plugin on the slave by removing their symlinks in /usr/local/ispconfig/server/plugins-enabled/ on the slave to prevent that the cronjob is added on the slave.
