• How to install and setup LXC Containers (OpenVZ alternative) on Centos 6 / 7


    If you don't aleady have it, you'll need EPEL Install LXC yum -y install lxc lxc-templates Loaded plugins: fastestmirror Setting up Install Process Loading mirror speeds from cached hostfile * base: mirror.it.ubc.ca * epel: mirrors.kernel.org * extras: mirror.it.ubc.ca * updates:........
  • How to qemu-kvm enable bridged networking in Debian Ubuntu Linux Mint on KVM containers


    I've read a few guides about this but they didn't work for me. sudo apt-get install bridge-utils #don't think the above is enough it won't work still even though you have by default an /etc/qemu-ifup that handles it if you have the right tools and setup sudo qemu-system-x86_64 -net tap -net nic -enable-kvm -cpu host,vmx=on ~/VirtualBox VMs/vsphere-vcenter/vsphere-vcenter.vdi W: /etc/qemu-ifup: no bridge for guest interface foun........
  • VirtualBox Nested Virtual Machine Containers with KVM Not Working no SVM or VMX module in the guest


    I can't get vmx cpu extensions to show up in Virtualbox guests despite enabling nested paging and enable vmx in virtualbox guest but this doesn't help that you check VT-X or the AMD Virtualization SVM it enables it for the guest to use BUT does not pass it through. This means if you check cat /proc/cpuinfo in the guest you will see the CPUdoesn't support virtualization. It looks like VirtualBox still hasn't implemented this! But there is good news I&n........
  • OpenVZ Migration Hostnode Containers from Centos 5 to Centos 6


    migrating from an old OpenVZ (Centos 5) to new OpenVZ (Centos 6) Also if migrating from 32-bit HN to 64-bit your RAM will probably be much bigger than it should be! 16x bigger eg. 32bit HN: total used free shared buffers cached Mem:&nb........
  • possible SYN flooding on port 80. Sending cookies.


    Errors like this are shown on high usage servers and ports so it is common to see it on http and even imap ports: possible SYN flooding on port 80. Sending cookies. The Linux kernel will even detect flooding on OpenVZ containers: possible SYN flooding on ctid 6000, port 993. Sending cookies. In many cases this is not an issue and is more so simply a result of regular, but high usage traffic.........
  • Openvz OOM Centos Issue Memory Config Settings Solution


    Linux box13. 2.6.32-042stab076.5 #1 SMP Mon Mar 18 20:41:34 MSK 2013 x86_64 x86_64 x86_64 GNU/Linux even setting privvmpages to a specific setting DOES not affect "free -m" in containers. This is probably a kernel issue 23:36:29 up 159 days, 7:12, 4 users, load average: 0.42, 0.44, 0.33 [root@box13 ~]# free -m total&n........
  • iptables v1.3.5: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) - OpenVZ Container Problem iptables module problem solution


    iptables v1.3.5: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) This solution applies to all other iptables modules/problems for OpenVZ, you'll just need to add them to both lists/lines below if you have modules other than what I have below. The modules need to be enabled in both iptables and the OpenVZ hostnode itself and then the containers which need it must be restarted. How To Enable IPTables Modules in OpenVZ........
  • Xen non-HVM container won't work/boot anymore


    One of my test Centos 5 containers was on a partition that filled up and it threw all sorts of errors and stopped responding but now I can't boot it again anymore. All the console shows is the Linux Penguin on the top left corner and the xm console says "usbcore: registered new driver hub" and has halted there. Centos 5 Xen container stuck/frozen won't boot on "usbcore: registered new driver hub" Another great way of troubleshooting is booting fro........
  • Openvz Container IP not working suddenly Solution


    This may not apply to everyone but here is what happened to me. One day my IP connectivity for one container went dead, I could ping the hostnode from it and the hostnode could ping it but there was no external routing. I restarted the network service but it didn't help. I checked the routing table inside the VPS and the host and everything looked normal. Iadded another different IPon the same subnet to the container and it worked. Right away I st........
  • OpenVZ iptables v1.3.5: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded. Solution


    This error is annoying, in a Virtuozzo KB entry about this ip tables nat problem they say the kernel needs to be ugpraded: Symptoms The node runs 2.6.18-x kernel older than 2.6.18-028stab053.10. NAT module does not work in container, you get "can't initialize iptables table 'nat'" error: # iptables -t nat........
  • OpenVZ backup container to a single file while it's running using "vzdump"


    Proxmox has made this free utility to backup running OpenVZ containers. It's a great program which is actually just a PERL script but gets the job done. This program is not 100% required because all it really does is cp -a from your container's path as far as I know but it is still good to have uniformity to how you backup your containers. For RPM distros such as Centos/RHEL/Fedora etc.. download and install this: wget http://www.proxmox.com/cms_proxm........
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