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system-maintenance Archives - AWS Managed Services by Anchor

SSH ControlMaster: The Good, The Bad, The Ugly

By | Technical | 6 Comments

Do you love SSH for the good it has done for mankind, but get annoyed by how long it takes to establish a connection over a high-latency connection? Perhaps you have a process that needs to make thousands of SSH connections, and you’d like a little extra speed from the whole thing. Either way, ControlMaster is your new best friend. The concept is very simple — rather than each new SSH connection to a particular server opening up a new TCP connection, you instead multiplex all of your SSH connections down one TCP connection. The authentication only happens once, when the TCP connection is opened, and thereafter all your extra SSH sessions are sent down that connection. If you’re SSHing between machines on the same LAN, or otherwise a short…

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“But I’ll remember it!” — why people don’t write documentation

By | Technical | One Comment

As I mentioned in my last documentation-related article, having a wiki or other documentation repository is really only a small part of the system documentation battle. What really counts is actually getting it chock full of all the knowledge in your organisation, and — possibly even more importantly — keeping it up-to-date forever and ever, Amen. Just telling people to document their work really doesn’t work. While a quick “hey everyone, write some docs!” might get a desultory page or two written, it’s not really enough. Writing things down needs to be as natural as breathing, and about as easy. In fact, you should really aim for it to be easier to write than to not write, so that the “natural” choice is to do it. Finding and eliminating the…

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The Zen of Documentation Maintenance

By | Technical | No Comments

Given that you’ve been suddenly and completely convinced of the need for documentation in my previous post, the question still remains: how does one make documentation appear on a consistent and ongoing basis? If you’re really, really lucky, you’ve been spared the painful experience of putting up a wiki somewhere (or, worse, forked out a pile of cash for a “knowledge management system”), sticking some info into it at random, and then… nothing. You planted the seeds of a documentation tree, why isn’t it growing, and flowering, and solving all of your problems for now and forever? For Project Starbug, we’re creating a whole new infrastructure, more-or-less from scratch. This is the easiest possible environment to make work, because you’re not constrained by what is already in place (and that…

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If you don’t write it down, it never happened

By | Technical | No Comments

You’re trying to reconfigure a service to do something new. Digging into the config files, you see that everything’s been modified heavily, but it doesn’t seem to make a lot of sense. Everything’s currently working, so it must be right, but why was it done like this in the first place? It looks like this can be simplified, but… you’re not sure. What if it needs to be this complicated for a reason? Or perhaps it’s 2am, you’ve just been notified by the monitoring system that a critical system that you don’t have a lot of experience with has gone down. Logging in to the server you thought the service was on, you realise that this isn’t the right place, so you waste precious time tracing the network through the…

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