09 Apr 16 Getting in love with Docker Machine!!
Docker is becoming the “today standard” of lxs linux containers.
I think I will avoid learning Kubernetes to handle dockerized hosts, and I will study Docker Engine, Docker Swarm and Docker Machine and its REST APIs instead.
I started from here: https://docs.docker.com/machine/overview/
01 Gen 16 Buon anno nuovo!
Auguri a tutti!
Buon anno nuovo!
28 Nov 15 How to enable HTML5 video playback in firefox
If you use Mozilla Firefox and you want to view video streaming with HTML5 embedded players, you may need to enable some video functionality into the firefox configuration.
For some reason obscure to me Mozilla Firefox will not play some HTML5 based video streaming, and the embedded player will probably fall back to Adobe Flash based streaming (that is what I don’t want since it’s closed source and it’s a very insecure application).
For example, youtube has a HTML5 based player that you could choose to use instead of flv. You can verify and enable HTML5 based streaming functionality of your browser navigating to https://www.youtube.com/html5.
In my case (Firefox 64 bit on Linux Debian) the tabs “Media Source Extensions”, “MSE & H.264” and “MSE & WebM VP9” are disabled by default.
If you want to enable those functionalities simply write “about:config” into the firefox navigation bar.
You will be alerted to pay attention to not modify things or your warranty will be broken.
Just ignore the warning and proceed.
Now, if you did not already, switch the following configuration parameters to true:
media.fragmented-mp4.exposed
media.fragmented-mp4.ffmpeg.enabled
media.fragmented-mp4.gmp.enabled
media.mediasource.webm.enabled
media.mediasource.enabled
If you try to refresh the HTML5 based youtube player, you should hopefully have all video streaming tabs ready and enabled.
If you want, you can now switch the youtube default player to HTML5.
04 Nov 15 Rescan iSCSI volume after resize on linux
If you need to resize a iSCSI volume you need to:
- resize the volume on the iSCSI target (ietd)
- rescan the volume on the iSCSI initiator (open-iscsi)
- resize the fs, if any
I’ll skip the resize procedure on the target, because it depends on how it’s made (lvresize, dd, etc).
The procedure to rescan the volume on the initiator (open-iscsi) is very simple and can be accomplished online.
iscsiadm -m node -R
Then, you can grow the filesystem, if any (xfs_grofs, resize_reiserfs, resize2fs, depending on your fs type).
30 Ott 15 How to check SSL/TLS protocol for a given server
If you need to check which SSL/TLS protocol version is implemented by your webserver, you can issue the following command:
dino@dam2knb:~$ echo | openssl s_client -connect 10.38.46.137:8443 2>&1 | grep Protocol
Protocol : TLSv1.2
30 Set 15 apache [error] (13)Permission denied: Cannot create SSLMutex
On one of the servers of one of my clients, a Solaris 5.8 sparc host, apache did not want to start.
It wrote the following error message on the error_log file:
cojo1@myserver $ cat error_log
[Wed Sep 30 12:24:11 2015] [error] (13)Permission denied: Cannot create SSLMutex
The problem, in my case, was about the permissions on /tmp.
Since these machines can be accessed by hundred people, someone thought well to change /tmp permissions to 0775. Everybody knows that if whould be 1777 instead.
The lack of both the sticky bit and write permissions to other did not make apache starting for non root users.
Hope this help someone.
Ciao, Dino.
08 Feb 15 Never say the truth to job interviews
After years of TI technical support middleware expert (and any offers received after a job interview that I had in june) it’s now time to explore new horizons, so I’m searching some new job.
In the meantime I’ll do the very minimum here at TI: I’ll turn my phone off and no more extra help to anyone.
NOTE1: never say the truth to job interviews;
NOTE2: never help heads and collegues;
NOTE3: never say you know something more or you’ll get new work for free;
NOTE4: always be cynic
27 Gen 15 How to get the device mapper name associated to LVM logical volumes
This is how to get the device mapper name (dm-1, dm-2, etc) associated to each LVM logical volume:
lvdisplay|awk '/LV Name/{n=$3} /Block device/{d=$3; sub(".*:","dm-",d); print d,n;}'
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