How to start services in certain order with Systemd?
Have been reading a bunch of documentation to figure this one out.
By the way, this also includes the SysV startup scripts (which are called by systemd).
So, in this below example (real situation), I have Docker that needs ocfs2 filesystem which runs on top of DRBD.
Default startup configuration was not quite ok because docker almost always started first and ocfs2 was started in the same time with drbd and failed to mount the ocfs2 filesystem.
Linux is powerful and whatever linux based, is powerful too.
Cygwin can help you in many ways and in this article I will explain how easy is to clone an entire disk with it.
Proprietary and costly applications? HA! :)
!!! WARNING !!!
>>> DO THIS VERY CAREFUL BECAUSE WRONG CHOICES CAN DESTROY DATA <<<
!!! WARNING !!!
Ever wonder how to connect via ssh to a windows machine?
Of course there are other ways but I like this one better because it allows you to access the most powerful tool ever created for Windows: cygwin :)
So, here we go.
1. Run cygwin as administrator
Right click on the cygwin icon and select "Run as administrator".
I can write tons of bla bla about block devices, UUID and all related but the internet (especially wikipedia) is full of this so I will let you do a search if you are more interested about any of this.
So, I will keep it simple: you arrived here because you need a fast way to see the UUIDs of your block devices (call them hdds, partitions, as you like).
There are various tools and commands to achieve that. Read on.
Some of us (like me) still have old macbooks that came with superdrive. Naturally, we have replaced it long time ago with a secondary disk.
Wondering what to do with the now apparent "useless" eject button?
Find below some useful key combinations.
Shows a dialog box with following options:
go to sleep
If you need (as I do) multitab support in mintty, you can have it with the help of ... wait for it ... SCREEN!
It was always there but I haven't got this brilliant idea to use it.
Also, do not get fulled about the title as this works in any linux like environment.
Some of you already know that Windows zip combines several different functionalities:
- compression (like gzip),
- archiving multiple files into one (like tar),
- encryption (like gpg),
- plus some other.
Unix and Unix-like operating systems tend to split them so do not be surprised to have gzip for compression, tar for archiving files into one and gpg to encrypt.
I use Maintenance app to do some checks and cache cleanup from time to time. Today I got a message that my disk should be checked and repaired while in recovery.
So I did and I was surprised to find out this error while checking/repairing /: snap_metadata_val object: invalid extentref_tree_oid
Apparently this is related to local snapshots of time machine and one of them is in weird state indeed:
You know how to pull and create custom images; do whatever with them.
But if you need the same custom image on multiple servers in your network, you will have to copy that image on them. Here comes docker registry: a local repository of your images.
And the installation of a local repository is done via (guess?) a container :).
Basically, all you have to do is to pull the registry image and run a container on top of it. As simple as that!
So I finally got a bit into docker because everybody is talking about it.
I will skip the installation part because it is not that difficult (easier than windows install actually: next, next, finish) and go straight to the interesting part: using docker commands.
I recently upgraded the debian version from 8 to 9 and my surprise was to not being able to connect to the newly upgraded server with my usual ssh key.
It turns out that beyond OpenSSH version 6.6, the "unsafe algorithms" have been removed, including my kinda old dss key.
All you have to do is to create a new one. I choose ecdsa: $ ssh-keygen -t ecdsa
Do not forget to put the newly pub key (e.g. the content of ~/.ssh/id_ecdsa.pub) in ~/.ssh/authorized_keys of the upgraded server.