Chris, On 5/5/15 4:39 PM, Chris Aguirre wrote: > I actually use Windows Powershell to execute commands on remote machines, > including stopping/starting Tomcat (and other Windows Services). > > This works well for me - but in this case, I have complete control of all > the VMs - and they are not Production Servers. > > I used the following articles as reference for creating the Powershell > scripts: > > http://www.howtogeek.com/117192/how-to-run-powershell-commands-on-remote-computers/ > > http://stackoverflow.com/questions/6239647/using-powershell-credentials-without-being-prompted-for-a-password
That's great. *NIX also has ssh which can be used to execute remote commands, but that's not the hard part. The hard part is planning a regular configuration that can be deployed to possibly hundreds of separate machines (virtual or physical) and then controlled in a sane way. For instance, let's say that I have 12 machines in two separate clusters. If I want to shutdown 3 machines in each cluster, I have to execute a flurry of commands like these: $ ssh -c user@server1 /path/to/tomcat/shutdown.sh $ ssh -c user@server2 /path/to/tomcat/shutdown.sh $ ssh -c user@server3 /path/to/tomcat/shutdown.sh $ ssh -c user@server7 /path/to/tomcat/shutdown.sh $ ssh -c user@server8 /path/to/tomcat/shutdown.sh $ ssh -c user@server9 /path/to/tomcat/shutdown.sh If I had a tool that understood my deployment configuration, I could do something like this: $ cluster shutdown 1 2 3 7 8 9 If the tool was *really* nice, it might inform my load-balancer that the nodes would be coming down as well. If it was super-nice, a tool would allow me to schedule a shutdown of nodes in the near future. For example, say I want to take those same nodes offline, but I want to disable them at the lb, then wait for their sticky sessions to drain folly before stopping each Tomcat instance. And since I don't want to watch the tool while it waits, I want to get an email or SMS confirmation when each node goes down. Maybe I can get integration into monitoring tools as well, so when I intentionally take a node offline, I don't get a bunch of text messages telling me that a server has gone down. These are the kinds of things that a "grid" tool could do to help. Being able to execute remote commands is just one of the primitive operations of this kind of thing. -chris
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