entropy inside a virtual machine

Posted on Thu 30 June 2016 in Linux • Tagged with ceph, kvm, linux, notepad • 1 min read

Sometimes my ceph-(test!)deployments inside a VM failed.

The Problem is that the kernel/cpu can not provide enough entropy (random numbers) for the ceph-create-keys command - so it stuck/hang. It is not a ceph problem! This can also happen with ssl commands.

But first things first - we need …

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Openstack Horizon - leapyear bug

Posted on Mon 29 February 2016 in openstack • Tagged with Openstack, SUSE Cloud 5, SUSE Cloud 6, linux, openstack, suse • 2 min read

Switching the language in the dashboard ends with a error.

"day is out of range for month"

eg. https://bugs.launchpad.net/horizon/+bug/1551099

[Mon Feb 29 09:20:05 2016] [error] Internal Server Error: /settings/
[Mon Feb 29 09:20:05 2016] [error] Traceback (most recent call last …

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openvswitch and OpenFlow

Posted on Fri 04 September 2015 in Linux • Tagged with ovs, linux, notepad, openflow, openvswitch • 2 min read


Layer 1

ovs-ofctl del-flow BRIDGE
ovs-ofctl add-flow BRIDGE priority=500,in_port=1,actions=output:2
ovs-ofctl add-flow BRIDGE priority=500,in_port=2,actions=output:1
ovs-ofctl dump-flows BRIDGE

Layer 2

ovs-ofctl del-flow BRIDGE
ovs-ofctl add-flow BRIDGE dl_src=00:00:00:00:00:01,dl_dst=00:00:00:00:00:02 …

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Gentoo - initramfs with busybox, lvm and some more...

Posted on Tue 11 August 2015 in Linux • Tagged with Gentoo, linux, notepad, initrd • 1 min read


mkdir -p /usr/src/initramfs/{bin,lib/modules,dev,etc,mnt/root,proc,root,sbin,sys}
cp -a /dev/{null,console,tty,sda*} /usr/src/initramfs/dev/


USE="static make-symlinks -pam -savedconfig" emerge --root=/usr/src/initramfs/ -av busybox

LVM provides already a static binary :)

cp /sbin …

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ldap initial configuration

Posted on Fri 06 March 2015 in Linux • Tagged with ldap, Linux, notepad • 1 min read

A more or less initial configuration for openldap (>2.4)

# to import run:
# ldapmodify -Y EXTERNAL -H ldapi:/// -f $filename
# to verfiy run:
# ldapsearch -Y EXTERNAL -H ldapi:/// -b "olcDatabase={1}hdb,cn=config"
# to create a password:
# slappasswd -h {SSHA} -s admin

dn: olcDatabase={1}hdb,cn=config
changetype …

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Monitoring a fritzbox via upnp - FritzOS 6.20 // FritzBox 7490

Posted on Wed 11 February 2015 in Linux • Tagged with fritzbox, upnp, notepad, linux • 1 min read

curl "http://fritz.box:49000/igdupnp/control/WANCommonIFC1" -H "Content-Type: text/xml; charset="utf-8"" -H "SoapAction:urn:schemas-upnp-org:service:WANCommonInterfaceConfig:1#GetAddonInfos" sion='1.0' encoding='utf-8'?> <s:Envelope s:encodingStyle='http://schemas.xmlsoap.org/soap/encoding/' xmlns:s='http://schemas.xmlsoap.org/soap/envelope/'> <s:Body> <u:GetAddonInfos xmlns …

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apache and tomcat - packetsize per request

Posted on Mon 05 January 2015 in Linux • Tagged with jboss, linux, notepad • 1 min read

During a consulting project i had some trouble with the following environment


Loadbalancer >> Apache >> Tomcat / JBoss

Each request ended in a 400 Bad Request but the configuration looks good and works fine with other projects.

In the end we made some configuration modifications to the apache and tomcat.

Configuration …

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systemd - abstract

Posted on Wed 13 August 2014 in linux • Tagged with systemd, linux • 1 min read

Rescue Mode


Analyzing the boot process

systemd-analyze blame  
systemd-analyze plot > /tmp/plot.svg

Start/Stop/Disable services

systemctl start/stop/restart/mask [service]  
systemctl daemon-reload  
systemctl list-units --type=[timer,service,target,mounts,...]


journalctl -u ssh  

Custom unit

http …

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Retrieve Windows key from ACPI MSDM table

Posted on Thu 19 June 2014 in Linux • Tagged with windows, hex, msdm, linux, notepad • 1 min read

[root@localhost ~]# hexdump -C /sys/firmware/acpi/tables/MSDM
00000000 4d 53 44 4d 55 00 00 00 03 d3 4c 45 4e 4f 56 4f |MSDMU.....LENOVO|
00000010 54 50 2d 47 32 20 20 20 70 25 00 00 50 54 4c 20 |TP-G2   p%..PTL |
00000020 02 …

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Syncing a fork with git/github

Posted on Mon 16 June 2014 in Linux • Tagged with git, HowTo, Linux, github, notepad • 1 min read

Configure a remote

git remove -v
# git remote add  
git remote add upstream https://github.com/foo/bar.git
git remove -v

Pull "upstream"

# git fetch 
git fetch upstream

Checkout the master

git checkout master

Merge "upstream" master to local master

# git merge /
git merge upstream/master

(optional) Delete old …

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