Archive for the ‘Linux’ Category
TAO: Facebook’s Distributed Data Store for the Social Graph
This post will be very succinct. Just a single link to a publication of TAO’s details at USENIX and a quote from the abstract part of the paper to catch your eye: We introduce a simple data model and API tailored for serving the social graph, and TAO, an implementation of this model. TAO is […]
Simple Python scp wrapper
Inspired by the following article I decided to write a simply python scp wrapper which is based on the ideas taken from the perl script also mentioned on the same page. The whole point of this wrapper is dead simple: to allow certain users scp into their specific directories with out granting full ssh access. […]
OpenLDAP do_syncrep retrying attempts
Do you observe the error messages on your Linux OpenLDAP replica or master server similar to the ones listed below: May 16 12:05:21 ldapserver1 slapd[5420]: do_syncrep2: rid=005 (-1) Can’t contact LDAP server May 16 12:05:21 ldapserver1 slapd[5420]: do_syncrepl: rid=005 rc -1 retrying (4 retries left) May 16 12:05:21 ldapserver1 slapd[5420]: do_syncrep2: rid=002 (-1) Can’t contact […]
How the SCP protocol works
That’s not my title but the one I stole from a fantastic Jan Pechanec’s blog post that describes how the SCP protocol works – https://blogs.oracle.com/janp/entry/how_the_scp_protocol_works I really encourage everyone to read it.
In: FreeBSD, HP-UX, Linux, Solaris
Regression in pam_listfile module in RHEL5.9
Hot on the heels of the recent support ticket we opened with RedHat that has been finally resolved. For those who have RHN access below is the direct link: https://access.redhat.com/knowledge/solutions/328433 In a nutshell. After upgrading to RHEL 5.9 we lost the ability to ssh into any of our servers where pam_listfile was configured and the […]
OpenLDAP with TLS, ppolicy and master-master replication on RHEL6.3
This post has been dusting on a draft shelf for too long. No reason to keep it there any loger. Below is the list of instructions which once followed would help anyone to end up with an OpenLDAP server on RHEL 6.1 (should work perfectly well with CentOS too). There is nothing special about it […]
OpenGrok, Ubuntu and Linux source tree
After all, thanks to our very long New Year holidays, I had a chance to install OpenGrok search and cross reference engine. The main reason is to have a tool to be able to efficiently browse Linux kernel source code. I use OpenGrok quite frequently, especially when there is a need to dive into Solaris/OpenSolaris […]
Spacewalk, osad and jabberd miscommunication
Spacewalk is really a handy tool if you want to keep your Linux infrastructure up to date. Especially if you run Redhat based ditro, since essentially it’s community supported version of Redhat’s product called Satellite. But it has a nasty issue, at least in our case, when the clients stop responding to the commands from […]
DLM lock levels in OCFS2
Yesterday I had to get a bit deeper into OCFS2 details and come across this very helpful blog post about different DLM lock levels used in OCFS2. Gave me a chance to place all the ducks in a row.
How to quickly fix osad failure to connect to the SpaceWalk server
If one day you noticed that you spacewalk client had started to spit at you with the following errors – just know that it’s very easy to fix. 2012/03/15 17:17:43 +04:00 29835 0.0.0.0: osad/jabber_lib.setup_connection(‘Connected to jabber server’, ‘spacewalk-server-name’) 2012/03/15 17:17:43 +04:00 29835 0.0.0.0: osad/jabber_lib.register(‘ERROR’, ‘Invalid password’) Stop spacewalk rhn-satellite stop rm -f /var/lib/jabberd/db/* Connect to […]