About Me

I've been professionally involved with Linux, networking and security since the late 90's working for various companies both in Europe and the US.

My areas of expertise include:

  • Designing, configuring, deploying and administering Linux environments, leveraging Redhat, CentOS, Ubuntu and Slackware distributions;
  • Linux clustering including RHCS, Pacemaker with Corosync and DRBD;
  • Load Balancing technologies including Stingray/Zeus, HAProxy and Pound;
  • Apache, Tomcat, Glassfish, MySql, Samba, Cobbler, Puppet and BIND servers;
  • MTA’s including Sendmail and Postfix;
  • Provisioning of new Linux servers using PXE with kickstart or Cobbler;
  • Linux files systems tuning of Ext 3, Ext 4, Reiserfs, NFS and GFS2;
  • Linux VPN technologies including openVPN;
  • Shell scripting with bash;
  • Linux kernel installation, tuning and patching;
  • Xen and KVM Virtualization technologies with libvirt, and openVSwitch
  • Centralized Authentication using OpenLDAP and Likewise;
  • Logical Volume Management on Linux with LVM2 and software RAID;
  • Networking and Network Protocols (TCP/IP and OSI models);
  • Cisco equipment (Routers and Switches);
  • System/Network Security Administration and Penetration Testing using SELinux, iptables, SNORT, OSSEC, Nessus and the Metasploit framework;
  • Cloud technologies including OpenStack, OpenShift and Amazon Web Services;

My Specialties are:

Virtualization and Cloud Infrastucture, Server Architecture, Application Architecture, Network Architecture, Middle-ware Infrastructure and Systems Administration.

For contact information check out my linkedin profile:

http://www.linkedin.com/in/konstantinivanov

In my spare time I love to travel. Here's a map of all the places I've lived or visited:


View Places I've Visited or Lived in a larger map

Konstantin Ivanov

7 comments:

  1. Hello there, thank you for the incredibly well written tutorials.

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  2. Благодаря много.

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  3. Very nice, more GEntoo pleeeease!

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  4. Hello,
    Sir, I am doing live migration of virtual machine using xen and kvm.I want to check the performance of transport protocol during live migration.So how can i change some parameters like quelen,tcp_rmmem etc on 100Mb/s link.I want to get some valuable effect after changing some tcp parameters.So pls help on this.

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  5. If you are using kernels from the 3. or 2.6 branches you are probably good out of the box, as those kernels come pretty well tuned. However you can benchmark your performance before tuning and after using the following kernel tunables and compare the results. On the servers that I manage they make about 30% difference in terms of requests per second. Of course the mem options might need adjusting based on how much memory your servers have, but at least you have a starting point:

    net.ipv4.conf.default.rp_filter=1
    net.ipv4.conf.all.rp_filter=1
    net.core.rmem_max = 8738000
    net.core.wmem_max = 6553600
    net.ipv4.tcp_rmem = 8192 873800 8738000
    net.ipv4.tcp_wmem = 4096 655360 6553600
    net.ipv4.tcp_tw_reuse = 1
    net.ipv4.tcp_max_tw_buckets = 360000
    vm.min_free_kbytes = 65536
    vm.swappiness = 0
    net.ipv4.ip_local_port_range = 30000 65535
    net.ipv4.tcp_syncookies = 0

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  6. Hi,
    Can you please share a important technic about server security(linux hardening).

    Thanks & your blog is very usefull for linux lovers.Keep it up :)

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  7. Please continue update your great ideas
    Thanks

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