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Simple VPN server configuration for easy VPN access to AWS using built in Windows VPN client. First to install pptp server package. sudo apt-get install pptpd Now to configuration: edit /etc/pptpd.conf option /etc/ppp/pptpd-options logwtmp localip 172.20.0.1  remoteip 172.20.0.10-50 edit  /etc/ppp/pptpd-options refuse-pap refuse-chap refuse-mschap require-mschap-v2 require-mppe-128 ms-dns 8.8.8.8 ms-dns 8.8.4.4 proxyarp nodefaultroute lock nobsdcomp mtu 1420 mru 1420 edit    /etc/ppp/chap-secrets  # client        server  secret                  IP addresses client1      pptpd   secret1      * client2      pptpd   secret2      * Add to /etc/rc.local iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE iptables -t mangle -A FORWARD -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu iptables -t mangle -A OUTPUT -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu Run: /

You might need to use apt-add-repository script and will get a missing command error. For example: sudo: apt-add-repository: command not found in order to fix that you nred to install  python-software-properties package # apt-get install python-software-properties That's it. Provided by: Forthscale systems, cloud experts

To stop Network Manger ( for example then using pacemaker cluster) execute as root: #  service NetworkManager stop To prevent Network Manager Service from starting at boot execute as root: # chkconfig NetworkManager off Keep in mind that you now need to manually configure your network interfaces. Provided by: Forthscale systems, cloud experts

To check  if SELinux is running execute following command: # getenforce To disable it, execute the following command: # setenforce Permissive This will put selinux in a passive (allow all) mode and last until the machine is rebooted.  To permanently disable it, change SELINUX= line in: /etc/sysconfig/selinux . Provided by: Forthscale systems, cloud experts

We needed to install CentOS 6.4 machines with USB and got into absolute madness. All RHEL cones have no working procedure and workarounds consisted of using FAT32 partition with 3rd party tools (problematic with install ISO files greater than 4GB) or multiple partitions and remounts. Until we found a very simple solution that did not work as well and fixed it. To create the USB You will need: Red hat based distribution to create the USB (in our case  CentOS-6.4-x86_64-bin-DVD1.iso) .  Actual CD iso image  Fedora  livecd-iso-to-disk script Steps are very simple: Insert the USB stick to the port. You need to find out the device name (for ex.  /dev/sdb1  ) On systems with auto-mount just run df -h or plug it in and run  dmesg | tail -20 Install livecd tools: yum install livecd-tools Make sure it is bootable  (for ex.  /dev/sdb1, via editing it`s parent - sdb  ): /sbin/parted /dev/sdb (parted) toggle 1 boot (parted) quit Format it with ext3 (does not support ext4)

IN a default installation on NX server root access is disabled. To allow root login just follow those simple steps. Edit file: /usr/NX/etc/server.cfg and substitute line reading #EnableAdministratorLogin = "0"  to: EnableAdministratorLogin = "1" save the file and exit. and run in shell as a root user: /usr/NX/bin/nxserver --useradd root this is it. Changes will take affect immediately.

Oracle provides a free and public yum server to update it`s Enterprise Linux distribution. It is easy to set-up and it supports versions 4, 5 and 6. To set up public repositories for different versions, download configuration file (for ex. with wget) In Oracle Enterprise Linux 6.x # cd /etc/yum.repos.d # wget https://public-yum.oracle.com/public-yum-ol6.repo In Oracle Enterprise Linux 5.x # cd /etc/yum.repos.d # wget https://public-yum.oracle.com/public-yum-el5.repo In Oracle Enterprise Linux 4, Update 6 or Newer # cd /etc/yum.repos.d # if you have old repo file then: # mv Oracle-Base.repo Oracle-Base.repo.disabled # wget https://public-yum.oracle.com/public-yum-el4.repo You can verify new configuration with: #   yum list And execute update with : # yum  update Provided by: Forthscale systems, scalable infrastructure experts

         How to install Vertica Analytic Database Download Vertica Download Vertica RPM from the site http://www.vertica.com/ For this tutorial we are using Community Edition 6.1.2-0, which is the latest version so far. This version has bug, that need to fixed manually in multiple nodes install, the bug will be fixed in next versions. Server preparation Before installing Vertica few things must be done on the server and some of the are optional(but strongly suggested). All this steps must be done on all nodes if installing multi node solution.         Must configurations Install Linux OS - we are using Centos 6.4 for this tutorial Check that the server is has at least 1 GB RAM free(minimum for install, we suggest     to have more memory for normal usage) [root@vertica01 ~]# free -m             total       used       free     shared    buffers     cached Mem:          1877        465       1412          0         14        343 -/+ buffers/cache:    

General Information PGPool can run on same server along with PostgreSQL DB or on stand alone server(recommended). In this article we will install PGPool on stand alone server, but the only difference is connection ports on PGPool and PostgreSQL. We will install PGPool II 3.1 on PostgreSQL 9.1. Basic architecture: ┏───────────────┓ │                │ │     pgpool-1    │ │  pgpool server │ │                │ ┗───────────────┛ //             \\ //               \\ //                 \\ \\//                \\// \/                  \/ ┏───────────────┓           ┏───────────────┓ │                │           │                │ │     pgsql-1     │ streaming │      pgsql-2    │ │  pgsql master  │══════════>│  pgsql slave   │ │     server     │replication│     server     │ │                │           │                │ ┗───────────────┛           ┗───────────────┛ Fail cases: Slave fails In case slave server will fai