Okay, I'll admit it. I don't actually know what devops is. I know what developers do and what sysadmins do. Is devops just a buzzword for one person who can do both? Or does it mean something other than that?
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Devops/Sysadmin Cheatsheet
21–30 of 110 posts
Re: Devops/Sysadmin Cheatsheet
#22Okay, I'll admit it. I don't actually know what devops is. I know what developers do and what sysadmins do. Is devops just a buzzword for one person who can do both? Or does it mean something other than that?
I will admit that I have a fuzzy understanding as well. My take on it is a holistic view and integration between development and operations instead of formal or informal walls between the two.
Wikipedia: http://en.wikipedia.org/wiki/Devops
In small companies it usually always exists by accident. I think the "hype" is more around large companies that have huge barriers and sometimes friction between development and IT or sustaining Operations.
Re: Devops/Sysadmin Cheatsheet
#23I would warn anyone that read this to understand what each command does before actually running anything on a machine. Things like "sudo !!" are INCREDIBLY dangerous, and I would never put that on a cheat sheet.
I suppose if you type it at any random point it might be. It's useful more when typed something that you forgot to sudo.
If you are running sudo, the long-term payoff is probably higher if you never use sudo !!. The very small chance of a huge disaster is still a lot higher than up arrow. Unless you are on a laggy connection and up arrow delays and you push it twice and end up running the wrong command!
If you have lots of jitter and lag, i suggest using Mosh which I've found to be amazingly awesome when using it on Amtrak's spotty free wifi (3G uplink).
Re: Devops/Sysadmin Cheatsheet
#24Thanks for this nice list.
Small nitpick/question: why put the commands in inputs? Do you edit them on that page? Or is it just to format them?
I tried to do a copy/paste on the page contents to my personal offline notebook but the most important bits, the commands, didn't paste.
Re: Devops/Sysadmin Cheatsheet
#25Great list. A few more (related or building on those there)
Quick mysql "why is my database under so much load suddenly" that doesn't rely on the slow query log:
pt-query-digest --processlist h= --interval=0.01 --print > /tmp/queries.out
pt-query-digest /tmp/queries.out
du -smc *
For 'ps auxww', throw on an f to get a visual representation of child processes.
And finally, ssh tunnels (which can be chained together) to get past bastion servers easily:
Host
HostName
ProxyCommand ssh -q "nc -w 3600 %h %p"Re: Devops/Sysadmin Cheatsheet
#26Checks the speed of the network. if you are looking to good connectivity on your VPS.
wget cachefly.cachefly.net/100mb.test -O /dev/null
dd if=/dev/zero of=iotest bs=64k count=16k conv=fdatasync && rm -rf iotestRe: Devops/Sysadmin Cheatsheet
#27[Edit oh gads I see now the commands are in text boxes and the full command is not visible. It is "ps aux | head -1 && ps aux | sort -k 4 -nr | head" which maybe correct is even more ridiculous.]
> ps aux | head -1 && ps aux | sort
Is a wasteful construct and doesn't even do what is claimed "List the top 10 memory hogs". Depending on what you consider "memory" something like this is shorter and correct.
ps aux --sort=-resident|head -11
Other errors: They list same command "du -hs" for twice. I believe they meant "df -h" for "overview of all disks". Although, it's correctly overview of mounted file systems.
Re: Devops/Sysadmin Cheatsheet
#28I would warn anyone that read this to understand what each command does before actually running anything on a machine. Things like "sudo !!" are INCREDIBLY dangerous, and I would never put that on a cheat sheet.
So, what's wrong with sudo !! then?
It re-executes your previous command -- this time with root privilege.
If and only if you meant to do that, you're fine.
Re: Devops/Sysadmin Cheatsheet
#29Earlier quoted context omitted.
I suppose if you type it at any random point it might be. It's useful more when typed something that you forgot to sudo.
If you are running sudo, the long-term payoff is probably higher if you never use sudo !!. The very small chance of a huge disaster is still a lot higher than up arrow. Unless you are on a laggy connection and up arrow delays and you push it twice and end up running the wrong command! If you have lots of jitter and lag, i suggest using Mosh which I've found to be amazingly awesome when using it on Amtrak's spotty fre…
I've never had any incidents with `sudo !!`, however, I should point out that zsh (maybe other shells as well) replaces the `!!` with the full command and requires another press of Enter.
$ rm -rf /root
rm: cannot remove `root': Permission denied
$ sudo !! # Does not run this, but returns the line below.
$ sudo rm -rf /root # Then you say, "Wait I dont want to do this."Re: Devops/Sysadmin Cheatsheet
#30A little gotcha: "iptables -L" doesn't list the NAT table rules; do "iptables -L; iptables -t nat -L" instead.
I also almost always add '-n' to iptables commands to disable reverse name resolution, which can sometimes take a while. Similarly when calling netstat.