• How to kill a docker swarm


    Assign way more replicas than you have of memory on all nodes and watch the Swarm crash which can easily reproduce in a small VMfor testing. root@Deb11Docker01:~# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAM........
  • docker swarm silly issues


    The error below can be caused by a gateway that is unpingable: docker swarm join --token SWMTKN-1-1kogg8da68gtb1j7ezaddowyy9s0an5s9tue758o20k18liskw-5h3f61hrrmv3u6agshvbtcklf 172.16.1.80:2377 Error response from daemon: manager stopped: can't initialize raft node: rpc error: code = Unknown desc = could not connect to prospective new cluster member using its advertised address: rpc error: code = DeadlineExceeded desc = context deadline exceeded........
  • Save money on bandwidth by disabling reflective rpc queries in Linux CentOS RHEL Ubuntu Debian


    Even today we see a lot of servers that have different services and ports open for rpc and this creates not only potential inward vulnerabilities but perhaps more common, the abuse of your network resources in reflective rpc queries. To stop this problem, you should disable and remove all services relating to rpc or at least block all relevant ports for the service. Surprisingly, there are still some providers and OS installs in Linux that install these services and leave them........
  • How to access a disk with bad superblock Linux Ubuntu Debian Redhat CentOS ext3 ext4


    Have you ever tried mounting a partition that you exists but you get this error? mount: /mnt: can't read superblock on /dev/sda1. The superblock in this example was bad because the physical disk had corruption and bad blocks/sectors. However, the data was generally accessible and you can always try this trick below (with caution and no warranty). This is specifically for filesystems that place superblocks in multiple locations, which........
  • Docker Swarm vs Kubernetes Comparison Guide


    A lot of companies are unsure which solution to choose and many may not be aware of Docker Swarm as an alternative to Kubernetes. One thing that many Sysadmins find is that Docker Swarm is simply easier, quicker to setup and maintain by far than Kubernetes.........
  • Proxmox How To Rename Node Hostname Fix Solution


    Proxmox's documentation shows the following here. Which mainly just says change /etc/hosts and /etc/hostname with your new hostname. Here's what happens if you only do that: If you just do the above, you will find you have an inaccessible original hostname that contains those VMs and you cannot........
  • Docker dockerd swarm high CPU usage cause solution


    If you have swarm services and dockerd is creating a high load even with the containers just being idle, the easiest solution is to upgrade to a newer docker version. For example an identical config of 3 nodes, with Redis 5 with 30 replicas produces a load of about 1.45 in Debian 10 with Docker18.09.1 If I create the same setup on Debian 11, with Docker 20.10.5+dfsg1 then the CPU usage is low. One other difference I wondered is the kernel. In my test setup........
  • debootstrap how to install Ubuntu, Mint, Debian install


    In this example we install debian 10 with --variant=minbase which gives us a minimal/tiny install. Don't use variant if you want the full size install. mkdir /tmp/deb10files debootstrap --variant=minbase buster /tmp/deb10files/ Did you get an error? debootstrap --variant=minbase buster /home/theuser/VMs/deb10files/ You'll get this error if you make a directory in your home........
  • GlusterFS HowTo Tutorial For Distributed Storage in Docker, Kubernetes, LXC, KVM, Proxmox


    This can be used on almost anything, since Gluster is a userspace tool, based on FUSE. This means that all Gluster appears as to any application is just a directory. Applications don't need specific support for Gluster, so long as you can tell the application to use a certain directory for storage. One application can be for redundant and scaled storage, including for within Docker and Kubernetes, LXC, Proxmox, OpenStack, etc or just your image/web/video files or even da........
  • Proxmox How To Enable Ceph Distributed Storage Cluster with OSD and Pools


    How To Install Ceph If you stopped an install of Ceph midway you will need to manually restart it with "pveceph install" Remember that your VM needs to have working internet (gateway) and DNS in order to connect to the apt repo to download all of the packages that Ceph requires. Remember to repeat these steps for each node that you want Ceph on. ........
  • Proxmox Services Won't Start Failed to start The Proxmox VE cluster filesystem. Proxmox VE firewall. PVE Status Daemon. Proxmox VE scheduler. PVE Cluster HA Resource Manager Daemon. PVE Local HA Resource Manager Daemon.


    There are many reasons why Proxmox services may not start, but one common one, is if you have changed your /etc/hostname or /etc/hosts and don't have a valid FQDN (eg. proxmox01 instead proxmox01.com). Failed to start The Proxmox VE cluster filesystem. Failed to start Proxmox VE firewall. Failed to start PVE Status Daemon. Failed to start Proxmox VE scheduler. Failed to start PVE Cluster HA Resource Manager Daemon. Failed to star........
  • How to install Kubernetes with microk8s and deploy apps on Debian/Mint/Ubuntu Linux


    Kubernetes Easy Beginners Architecture Guide Kubernetes is known as container orchestration and we should start at explaining the container part of it. A Container is what runs the actual application and based on an Image, and are more comparable to something like an LXC Container, Virtuozzo/OpenVZ using the Linux Kernel Namespaces feature. Containers run these images as independent, isolated operating environments under the OS's exist........
  • Juniper JunOS Command Overview and Howtos Switch, Router, Firewall Tutorial Guide


    Enable "cli" mode equivalent in JunOS cli Configure Mode configure So rather than going to the console on a Cisco switch and typing "enable" and then "conf t", the equivalent in JunOS is "cli" and "configure". How Do You Apply Changes You've Made? You can make all kinds of changes to the switch, but remember they are not........
  • ?? Question Marks for time, permissions and size of a file?


    -?????????? ? ? ? ? ? shadow ----------. 1 root root 748 Jul 10 04:35 shadow- cat: shadow: Input/output error If you see this you are probably in big trouble, it could be a physical error or if it's a VM image that it is corrupted due to a physical error on the underlying disk/array/NAS or it could a........
  • Radeon R3 GPU on Debian Crashing


    Occasionally my whole screen locks up and I cannot even swith to the console and I find this in my syslog: *-display description: VGA compatible controller product: Mullins [Radeon R3 Graphics] vendor: Advanced Micro Devices, Inc. [AMD/ATI]  ........
  • Linux Console Login Screen TTY Change Message


    This is all controlled by /etc/issue You can basically enter anything in there that you like, but there are preset variables that are mentioned at the end of the page that discuss this. Some examples of /etc/issue: Centos 7: S Kernel r on an m Ubuntu 16.04: Ubuntu 16.04.6 LTS n l You can also insert any of t........
  • Cisco Unified Communications Manager 12 Install Errors on Proxmox/KVM


    The strange thing is that usually the first install or two will work on any new machine but then it suddenly won't. I had this experience on QEMU 2.13 on a different machine. There is something finicky or buggy about the CUCM installer even when choosing the same virtual hardware specs. qemu-kvm command: /usr/libexec/qemu-kvm -version QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard ........
  • proxmox vm networking breaks when you restart your network on the hostnode


    Idid a systemctl restart networking and it broke Proxmox VM connectivity! #proxmox is the problem after restarting the network the tap devices go to disabled state [2230884.919905] vmbr0: port 7(tap118i0) entered disabled state [2230884.948864] vmbr0: port 8(tap122i0) entered disabled state [2230884.972748] vmbr0: port 6(tap119i0) entered disabled state [2230885.004745] vmbr0: port 5(tap117i0) entered disabled state [2230885.03673........
  • Centos 7 Reallocate logical volume space to another


    Do you hate how Centos 7 defaults to allocating most of your valuable space to /home even though it is a production server? Here is a quick guide on how to take back that space live, while online (of course make sure you have backups just in case something goes wrong!): First we will reduce our home dir by 100G: lvreduce -L -100G /dev/mapper/centos-home WARNING: Reducing active and open logical volume to ........
  • DRBD Errors Caused By Physical Corruption


    In a RAID array I had a have periodically lost a drive here and there over the past several months. Iwas always able to readd and resync without losing data. However at some point it looks like some minor corruption happened and this makes DRBD unhappy. Using fsck did not help either. Dec 19 06:01:45 storageboxtest4 kernel: [19005.945890] EXT3-fs error (device drbd0): ext3_get_inode_loc: unable to read inode block - inode=22184379........
  • How Does Cisco CUCM (Cisco Unified Communication Manager) Work?


    Cisco's CUCM (Cisco Unified Communication Manager) is a system that combines voice, video, data and mobile products into a single unified management suite. At its core, the CUCMis like a "Super PBX" that controls the flow of all communications through an organization even single or multiple site deployments. Cisco's CUCMmakes communication more effective and simple through centralized management and unification of communications resources.........
  • systemd management using systemctl and journalctl to check systemd logs


    systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system. The key commands or arguments you will use with systemctl are the following: Unit Commands: list-units [PATTERN...] List loaded units &nbs........
  • hwloc-nox set CPU affinity in Linux


    sudo apt-get install hwloc-nox Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: hwloc-nox 0 upgraded, 1 newly installed, 0 to remove and 530 not upgraded. Need to get 151 kB of archives. After this operation, 453 kB of additional disk space will be used. Get:1 http://archive.ubuntu.com/ubunt........
  • VMWare Vsphere VCSA Graphical Install Creates json


    yes it does create its own json ============================================ cat /tmp/vcsaUiInstaller/ovftool-20180809-175238948-20180809-175603497.log |grep -i json 2018-08-09T17:56:04.238-07:00 verbose OVFTool[30966] [Originator@6876 sub=Default] Manifest file entry: SHA1(VMware-vCenter-Server-Appliance-6.7.0.12000-8832884_OVF10-file1.json) = 1deb658c724767697587d5909c4051c01813e6a1 --> ........
  • Ethereum Client Errors


    INFO [07-19|12:11:51] Imported new block receipts count=590 elapsed=8.440s bytes=74117699 number=4870906 hash=6bc60b…934753 ignored=0 INFO [07-19|12:11:57] Imported new state entries count=499 elapsed=9.963ms processed=71076 pending=1526 retry=2&nbs........
  • Linux Centos 7 HowTo Install Yarn


    https://yarnpkg.com/lang/en/docs/install/#centos-stable curl --silent --location https://dl.yarnpkg.com/rpm/yarn.repo | tee /etc/yum.repos.d/yarn.repo If you need node.js: curl --silent --location https://rpm.nodesource.com/setup_6.x | bash - yum install nodejs yarn........
  • linux mint image convert menu option missing solution


    Ialready have the caja-image-converter option installed but it shows nothing. Weirdly enough if you install nemo and nautilus converter it does show and work inside caja: The solution is to install *-image-converter sudo apt-get install *-image-converter Reading package lists... Done Building dependency tree Reading state information... Done Note, selecting 'n........
  • Linux input/output error invalid program cannot read data on some CD-Rs and DVD-Rs on ASUS BW-16D1HT


    I've never seen this before in all of my years. Ihave some very old CDs and DVDs 12-15 years old that seem not to work in this BD-R/DVD-R/CD-R Asus drive. The discs are fine actually and ironically they even work fine on a normal LG USB based BD-R drive! Here are the errors in Linux: [2914936.884924] attempt to access beyond end of device [2914936.884927] loop1: rw=0, want=730424, limit=688384 [2914954.556873] attempt to........
  • Centos 6.6/6.9 KVM VM Kernel Panic On Boot - Kernel panic - not syncing: Attempted to kill init!


    Iam not sure why this is happening neither the hostnode or VM changed. All I did was reboot the hostnode and startup the Centos VM again, also note it happened with the original kernel on the VM and also the latest 6.9 kernel as of this writing as shown below. Host Node: Centos 6.9 Kernel:2.6.32-696.6.3.el6.x86_64 Kernel: 2.6.32-042stab123.9 Same result in any kernel above........
  • How to change reserved blocks in Linux partition


    user@box:~$ sudo tune2fs -l /dev/md99 [sudo] password for user: tune2fs 1.42.9 (4-Feb-2014) Filesystem volume name: Last mounted on: /mnt/md50 Filesystem UUID: 976a8655-2619-4587-878c-dab07f7b7652 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Fi........
  • USB 3.0 External HDD Enclosure Seagate UAS problems - [sdd] tag#1 CDB: Write(16) 8a 00 00 00 00 01 70 04 08 68 00 00 00 08 00 00


    This is a 8TB Seagate external USB 3.0 device apparently newer kernels use a module called "UAS" instead of "USB Storage" which causes issues as a lot of devices are not properly supported in UAS mode by the kernel driver. The solution some say is to disable UAS specifically for your USB device but I'd rather just disable UAS altogether. Solution blacklist UAS: *do not do this it does not work and just causes your USB 3.0........
  • [warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?) - Apache Error Solution


    Does this mean? [warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?) Basically it means you created your SSL Certificate as a CA the wrong way, usually with this command: openssl req -new -x509 -nodes -days 1530 -out server.crt -keyout server.key How can you fix it and do it properly? Step 1.) Make a new Private KeyCreate server pass key:........
  • mdadm frozen and doesn't realize array is dead/missing failed due to unplugged drives


    This was a surprising bug but I unplugged all drives for an array md127. At first it was just 1 drive and mdadm seemed to notice this. I unplugged the second drive taking the array offline but mdadm did not realize it was offline and still showed a non-existent disk as being part of it. This created problems trying to unmount it or even to stop this array with mdadm freezing. As for how to fix it I can only think of making sure you are not in a mounted path of........
  • DRBD Split-brain solution


    Uh oh [17925926.174277] block drbd0: Handshake successful: Agreed network protocol version 96 [17925926.174325] block drbd0: conn( WFConnection -> WFReportParams ) [17925926.174342] block drbd0: Starting asender thread (from drbd0_receiver [1682]) [17925926.174432] block drbd0: data-integrity-alg: [17925926.174581] block drbd0: drbd_sync_handshake: [17925926.174586] block drbd0: self 2AAE66AF9252D6DB:2815BF........
  • mdadm kernel panic if trying to change --layout on a RAID10


    It is already known this is not possible mdadm --create /dev/md3 --level 10 --layout=f2 --raid-devices=2 /dev/sdc1 /dev/sdd1 mdadm: /dev/sdc1 appears to be part of a raid array: level=raid10 devices=2 ctime=Sat Dec 24 18:44:29 2016 mdadm: /dev/sdd1 appears to be part of a raid array: level=raid10 devices=2 ctime=Sat Dec 24 18:44:29 2016 Continue creating ar........
  • mcp55 NIC not working at boot on Centos 6.6-6.8


    forcedeth 0000:00:08.0: irq 25 for MSI/MSI-X forcedeth 0000:00:08.0: eth0: MSI enabled forcedeth 0000:00:08.0: eth0: no link during initialization ADDRCONF(NETDEV_UP): eth0: link is not ready forcedeth 0000:00:08.0: eth0: link up ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready Dec 1 18:21:32 box15 kernel: forcedeth: Reverse Engineered nForce ethernet driver. Version 0.64. Dec 1 18:21:32 box15 kernel........
  • 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........
  • OpenVZ Error: Failed to load 2nd level quota solution


    Syncing private Live migrating container... Syncing 2nd level quota 11000: invalid option -- F Usage: vzdqload quotaid [-c file] commands Loads user/group qouta information from stdin into quota file. -c file use given quota file Commands specify what user/group information to load: -G grace time -U disk limits........
  • heartbeat cross talk


    I do not understand why heartbeat would try to communicate with another system not considered part of the node: heartbeat: [8280]: WARN: string2msg_ll: node [otherbox.com] failed authentication ........
  • blocked for more than 120 seconds issues with iowait and timeout on Live Linux distribution while writing to physical disk


    This happened while an mdadm array was syncing, all access from writing a new blank file to opening a small .txt file was very slow: [222117.312078] kjournald starting. Commit interval 5 seconds [222117.685060] EXT3-fs (md0): using internal journal [222117.685096] EXT3-fs (md0): mounted filesystem with ordered data mode [222122.376847] kjournald starting. Commit interval 5 seconds [222122.602825] EXT3-fs (md2): using internal jour........
  • OpenVZ how to enable FUSE in the container


    vzctl set 2 --devnodes fuse:rw --save Where "2" is the ctid........
  • Centos 6 how to guide convert LVM non-RAID into mdadm 1/10 RAID array live without reinstalling


    Here is the scenario you or a client have a remote machine that was installed as a standard/default minimal Centos 6.x machine on a single disk with LVM for whatever reason. Often many people do not know how to install it to a RAID array so it is common to have this problem and why reinstall if you don't need to? In some cases on a remote system you can't easily reinstall without physical or KVM access. So in this case you add a second physical or disk or already ha........
  • Openvz Enable netadmin


    vzctl set $CTID --devnodes net/tun:rw --capability net_admin:on --save........
  • ssh session and port forward or reverse port matching or assocation howto


    Use netstat with the -anpe option. The e option shows the inodes and I do not know if it will always work or if it was by fluke but I was dealing with dozens of SSHsessions and needed to know which session was related to which forward (the PIDs of the SSHand SSHD did not match etc...) Notice the "59560675" and "59560762" those are almost identical, if you find two sets that are nearly identical except for the last 3 digits they may match (in my ca........
  • ECC Errors in action


    Message from syslogd@server at Sep 14 11:35:59 ... kernel:[Hardware Error]: MC4 Error (node 1): DRAM ECC error detected on the NB. Message from syslogd@server at Sep 14 11:35:59 ... kernel:[Hardware Error]: Error Status: Corrected error, no action required. Message from syslogd@server at Sep 14 11:35:59 ... kernel:[Hardware Error]: CPU:6 (10:8:0) MC4_STATUS[Over|CE|MiscV|-|AddrV|CECC]: 0xdc00400021080813........
  • cPanel how to force reinstall rpms and fix packages and other problems caused by updates or duplicate rpms


    If a service is not working and resetting it to defaults is not working and you get bizarre error messages it is probably a broken update and possibly duplicate package. Take in this case "exim" not working even after resetting to defaults. Check for duplicates: rpm -aq|grep exim ........
  • Vbox/Virtualbox devices grayed out for non-root user solution


    It is a permissions issue that is hard to fix. All but one USB device is greyed out. I am already a member of "vboxusers" I have already enabled and disabled USB support for the guest. I have already reinstalled the latest VBOx guest editions If running as root it all works fine Changing........
  • Openvz iptables v1.4.7: 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


    iptables -t nat -A PREROUTING -p tcp -m tcp -d 192.168.2.1/32 --dport 3389 -j DNAT --to-destination 192.168.5.2:3389 iptables v1.4.7: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded. The above is often because you don't have the correct modules loaded on the hostnode or enabled for the container but in some cases it's actually a weird openvz setting. Che........
  • Openvz 2014-08-12T19:05:55-0400 vzctl : CT 391801 : Unable to start init, probably incorrect template 2014-08-12T19:05:55-0400 vzctl : CT 391801 : Container start failed


    2014-08-12T19:05:55-0400 vzctl : CT 391801 : Unable to start init, probably incorrect template 2014-08-12T19:05:55-0400 vzctl : CT 391801 : Container start failed This was caused by trying to run a 64-bit template on a 32-bit kernel hostnode which is obviously impossible. The solution is to use a 32-bit template or upgrade the hostnode to 64-bit.........
  • heatbeat ERROR: NV failure (msgfromsteam): [>>> ] ha_msg_add_nv_depth: line doesn't contain '='


    Apr 17 11:55:47 Cluster01 heartbeat: [1426]: WARN: ha_msg_add_nv_depth: line doesn't contain '=' Apr 17 11:55:47 Cluster01 heartbeat: [1426]: info: >>> Apr 17 11:55:47 Cluster01 heartbeat: [1426]: ERROR: NV failure (msgfromsteam): [>>> ] I have never been able to reproduce the above but it happened on heartbeat-3.04-2 when Itook a node down for testing. One thing Ibelieve caused it was by configuring ha.cf........
  • drbd howto solve splitbrain or WFConnection


    On primary node drbdadm connect all On secondary node drbdadm -- --discard-my-data connect all ........
  • [Hardware Error]: CPU:0 MC4_STATUS[-|CE|MiscV|-|AddrV|CECC]: 0x9c054c84011c011b [Hardware Error]: cache level: L3/GEN, tx: GEN, mem-tx: RD [Hardware Error]: Northbridge Error (node 0): L3 data cache ECC error.


    This server has been running for weeks without issue, it's currently only using 1 of 2 CPUs as it is running in the office as a test bed (mainly due to the handle 12 bay storage/great for testing HDDs). The errors below seem to mainly be from AMD CPUs, it's only happened a single time and in the days since Igot that error it hasn't occurrred. Interestingly enough /proc/cpuinfo still shows all 4 cores of the CPU (Opteron 2373 Quadcore HE) and the functionality doesn't seem........
  • 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........
  • strange kernel dmesg errors


    Sep 26 16:56:21 box kernel: 00 00 00 00 00 00 00 00 Sep 26 16:56:21 box kernel: [37007.155690] d_alias libdl-2.12.so d_count=9 d_flags=8 Sep 26 16:56:21 box kernel: [37007.155697] 09 00 00 00 08 00 00 00 9f 05 9f 05 00 00 00 00 c0 71 1d 18 04 88 ff ff 00 00 00 00 00 00 00 00 a0 7e 48 00 00 c9 ff ff 78 a9 21 18 04 88 ff ff 3a 7b fa 4e 0d 00 00 00 98 5c 2d 18 04 88 ff ff 18 5c 2d 18 04 88 ff ff 18 5c 2d 18 04 88 ff ff 00 01 10 00 00 00 ad de 00 02 20 00 00 00 ad de f8........
  • mkdir: cannot create directory 'test': Disk quota exceeded - Solution


    mkdir: cannot create directory 'test': Disk quota exceeded You are out of inodes usually: df -i Filesystem Inodes IUsed IFree IUse% Mounted on /dev/simfs 200000 200000 0 100% / none ........
  • EXT4-fs error (device md20): ext4_add_entry: bad entry in directory #2552670:


    Jun 12 10:30:53 kernel: [724514.291670] EXT4-fs error (device md20): ext4_add_entry: bad entry in directory #2552670: rec_len % 4 != 0 - offset=216, inode=2553603, rec_len=94, name_len=84 Jun 12 10:30:53 kernel: [724514.292400] EXT4-fs error (device md20): ext4_add_entry: bad entry in directory #2552670: rec_len % 4 != 0 - offset=216, inode=2553603, rec_len=94, name_len=84 This happened when an unprivileged user was backing up a Windows filesystem, once they ha........
  • iptables v1.4.10: can't initialize iptables table `filter': Table does not exist (do you need to insmod?)


    I have iptable_filter loaded on the hostnode so I don't understand this issue.........
  • xen how to resize an image properly


    The best way I could figure out is to use another guest of some sort to do this, while assigning the disk that needs to be resized to the same guest. So say we have /dev/xvda as the guests drive and we've booted it up. We also have /dev/xvdb (this is going to be the image/disk to be resized). In this case it's based on an ext3/4 image. Run e2fsck on it to ensure there are no filesystem errors. e2fsck /dev/xvdb........
  • 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........
  • Directadmin Enable SSL


    It's really silly how DA doesn't enable SSL by default but is otherwise a stable, fast and secure control panel. Here's a copy and paste way of enabling SSL for Directadmin in just a few seconds: *setup SSL openssl req -x509 -newkey rsa:1024 -keyout /usr/local/directadmin/conf/cakey.pem -out /usr/local/directadmin/conf/cacert.pem -days 9999 -nodes That creates the public certificate and private key pair in the location Directadmin expects to fi........
  • KVM QEMU and Xen how to mount disk images off-line and access data


    fdisk -lu VPS.img last_lba(): I don't know how to handle files with mode 81ed You must set cylinders. You can do this from the extra functions menu. Disk VPS.img: 0 MB, 0 bytes 255 heads, 63 sectors/track, 0 cylinders, total 0 sectors Units = sectors of 1 * 512 = 512 bytes Device Boot Start End ........
  • mdadm/Debian problem


    This is one in a series of weird things whichIthought was motherboard related (I RMA'd the motherboard), the RAM tests fine with memtest86 and I used badblocks on both RAID 1 members with no errors and smartctl is happy with them. Basically the array crashes the kernel a lot and has issues when writing. [112322.723465] md0: rw=0, want=14958668696, limit=1887460480 [112322.731077] attempt to access beyond end of device [112322.731087] md........
  • Linux Kernel Panic Messages - Symptoms of bad RAM module/stick


    These were caused by a bad stick of Corsair RAM [] free_hot_cold_page+0xfc/0x150 [] __pagevec_free+0x14/0x1a [] release_pages+0x127/0x12f [] __pagevec_release+0x15/0x1d [] __invalid_mapping_pages+0x120/0x156 [........
  • 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 migration error solution Error: Failed to suspend container CPT ERR: f68cf000,25000 :foreign process 15755/14731(vzctl) inside CT (e.g. vzctl enter or vzctl exec). CPT ERR: f68cf000,25000 :suspend is impossible now.


    Starting online migration of CT 25000 to 192.168.5.1 Preparing remote node Initializing remote quota Syncing private Live migrating container... Error: Failed to suspend container CPT ERR: f68cf000,25000 :foreign process 15755/14731(vzctl) inside CT (e.g. vzctl enter or vzctl exec). CPT ERR: f68cf000,25000 :suspend is impossible now. CPT ERR: f68cf000,25000 :foreign process 15755/14731(vzctl) inside CT (e.g. vzctl enter or........
  • How To Test If Your Hard Drive Is Good/Signs of dying hard drive


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  • Linux High IOWAIT updatedb can't be killed and crash with mdadm


    high IO wait 424 root 39 19 1900 848 552 D 0.0 0.0 0:00.91 updatedb root 424 0.0 0.0 1900 848 ? DN Mar11 0:00 /usr/bin/updatedb -f sysfs?rootfs?bdev?proc?cpuset?binfmt_misc?debugfs?sockfs?usbfs?pipefs?anon_inodefs?futexfs?tmpfs?inotifyfs?eventp........
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    yum -y install openssl* gcc-c++ gcc flex g++ make;wget http://www.directadmin.com/setup.sh;chmod +x ./setup.sh;./setup.sh #enable SSL /usr/bin/openssl req -x509 -newkey rsa:1024 -keyout /usr/local/directadmin/conf/cakey.pem -out /usr/local/directadmin/conf/cacert.pem -days 9999 -nodes chown diradmin:diradmin /usr/local/directadmin/conf/cakey.pem chmod 400 /usr/local/directadmin/conf/cakey.pem sed -i "s/SSL=0/SSL=1/g" /usr/local/dire........
  • Openvz Enable TUN/TAP OpenVPN


    Make sure the module "tun" is loaded on the host. vzctl set 2000 --devnodes net/tun:rw --save *Note what's below is what OpenVZ says you need (but I've never had to do it) vzctl exec 2000 mkdir -p /dev/net vzctl exec 2000 mknod /dev/net/tun c 10 200 vzctl exec 2000 chmod 600 /dev/net/tun On the container test the device: when Something is wrong:........
  • Dovecot Enable SSL/TLS with your certificate


    Dovecot enable SSL (by default it uses an old expired cert if you choose pop3s and imaps as protocols) =================== Create Cert & Key: openssl req -new -x509 -nodes -days 1530 -out server.crt -keyout server.key mkdir /etc/mailssl chmod 700 /etc/mailssl cp server.* /etc/mailssl Edit /etc/dovecot.conf ssl_cert_file = /etc/mailssl/server.crt s........
  • Postfix Enable SSL/TLS with your certificate


    Create Cert & Key: openssl req -new -x509 -nodes -days 1530 -out server.crt -keyout server.key mkdir /etc/mailssl chmod 700 /etc/mailssl cp server.* /etc/mailssl Postfix SSL config Edit /etc/postfix/main.cf: #SSL stuff smtpd_tls_cert_file = /etc/mailssl/server.crt smtpd_tls_key_file = /etc/mailssl/server.key To make smtps w........
  • CPU #1 not responding - cannot use it.


    I think this will be useful to others because I have a server that kept crashing mysteriously during intense disk usage/RAID checks. It would only crash during the weekly RAID integrity check. ThenI noticed during a reboot that not all CPUs were being brought up, as a result this actually creates much higher temperatures with the output I got from sensors, just booting the system produced higher than normal temperatures. You can imagine that a full blown RAID check........
  • Openvz Disk quota exceeded inode problem with free space


    Openvz problem, it is confusing because it's an inode issue and there is enough free space. cp: cannot create regular file `forums/memberlist.php': Disk quota exceeded /dev/simfs 60G 20G 41G 33% / none 2.0G 4.0K 2.0G 1% /dev........
  • updatedb/mdadm caused a kernel panic?


    Jan 16 04:02:03 centosbox syslogd 1.4.1: restart. Jan 16 04:07:34 centosbox kernel: INFO: task updatedb:20771 blocked for more than 300 seconds. Jan 16 04:07:34 centosbox kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Jan 16 04:07:34 centosbox kernel: updatedb D F78BE050 6476 20771 20766&n........
  • Ubuntu 9.04 Crash


    CPU/Kernel/MB/RAID problem? Jan 5 12:45:05 testbox kernel: [653298.890004] BUG: soft lockup - CPU#0 stuck for 61s! [hal-acl-tool:4168] Jan 5 12:45:05 testbox kernel: [653298.890005] Modules linked in: vmnet vmci vmmon binfmt_misc drbd video output input_polldev ocfs2_stackglue ocfs2_dlmfs ocfs2_dlm ocfs2_nodemanager configfs k8temp hwmon_vid lp snd_hda_intel snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi........
  • Ubuntu/Debian DRBD 8.0 Setup Guide


    I've only used it on Centos, soI thought I'd make a quick Debian guide: Install the DRBD Package apt-get install drbd8-utils Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: libswfdec-0.8-0 Use 'apt-get autoremove' to remove them. The following........
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    The Xen VPSI had was not working properly and when they asked for the login information I found the support was coming directly from India: whois 122.178.148.* [Querying whois.apnic.net] [whois.apnic.net] % [whois.apnic.net node-5] % Whois data copyright terms http://www.apnic.net/db/dbcopyright.html inetnum: 122.178.128.0 - 122.178.191.255 netname:&........
  • mdadm won't boot due to fsck error


    Nov 29 20:17:58 ubuntu kernel: [ 1157.180789] md: md1 stopped. Nov 29 20:17:58 ubuntu kernel: [ 1157.180829] md0: unknown partition table filesystem not responding/reading properly with du or rsync (this needed an fsck). [ 2571.489217] EXT3-fs error (device md2): ext3_lookup: deleted inode referenced: 35923106 [ 2571.942299] EXT3-fs error (device md2): ext3_lookup: deleted inode referenced: 35923110 [ 2571.9568........
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  • DRBD WFConnection Problem/Solution


    This has stumped me a few times because I keep forgetting that Centos 5.5 comes with a default iptables configuration that ends up blocking DRBD traffic,I tried all the normal things and couldn't understand why I couldn't make my normal DRBD config work. So if you have WFConnection problems and have tried the normal "mailing list" fixes, check your firewall status first! Both Nodes Say the Following: version: 8.3.8 (api:88/prot........
  • Openvz Live Migration Error - Error: undump failed: Invalid argument Restoring failed: Error: iptables-restore exited with 2 Error: Most probably some iptables modules are not loaded Error: rst_restore_net: -22


    Adding IP address(es): 192.168.5.8 192.168.5.9 Setting CPU units: 1000 Error: undump failed: Invalid argument Restoring failed: Error: iptables-restore exited with 2 Error: Most probably some iptables modules are not loaded Error: rst_restore_net: -22 Container start failed Stopping container ... Container was stopped Container is unmounted Error: Failed to undump VE Resuming... vzquota : (erro........
  • VirtualBox OSE/VBOX Can't Access Shared Folder Solution


    I shared a directory on my hostnode/local system (running Ubuntu 10.04) with my Guest system running Windows XP. I have no idea why it's not mentioned or documented in an obvious way, but in the Windows client you just access it with "\Vboxsvr" Once you access that share you'll have access to all of the VBOX shares on your local host. I think it should indicate it somewhere when you enable the sharing. Yes, I'm sure it's buried so........
  • 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........
  • FUSE/Curlftpfs mount ftp account as drive partition in Linux


    This is a great way to use your ftp server space, for example on your web hosting account (althoughI believe many hosts don't allow storage like this), but if you have a VPS/Dedicated Server etc.., this would be perfect. Imagine how easy it is to work with an ftp account that you can just mount as a normal partition or directory in Linux, it would be great for backups etc.. Name curlftpfs - mount a ftp host as a local directory Synopsis........
  • Openvz Enable Most Common iptables modules


    The default options for iptables are very basic. Here is what you need to do in order to enable them in OpenVZ. 1.) Add the modules to iptables and restart iptables: vi /etc/sysconfig/iptables-config Edit the line as so: IPTABLES_MODULES="ipt_REJECT ipt_tos ipt_TOS ipt_LOG ip_conntrack ipt_limit ipt_multiport iptable_filter iptable_mangle ipt_TCPMSS ipt_tcpmss ipt_ttl ipt_length ipt_state iptable_nat ip_nat_ftp" 2.........
  • Unixbench Score on Core i5 750 with OpenVZ Kernel vs Xen/Openvz


    This was unbelievable how much the Xen kernel slows things down, keep in mind both tests were done on the hostnode, one was with the Openvz-Xen hybrid kernel and the other was just OpenVZ. You can see the performance difference is nearly 300% better when not using the Xen kernel. OpenVZ-Xen Kernel Test Results (I was wondering what was wrong/so slow with my Core i5!) # # # # # #&n........
  • Starting online migration of CT 300 to 192.168.5.45 Error: vzcpt module is not loaded on the source node Error: Can't continue online migration Error: vzcpt module is not loaded on the source node Error: Can't continue online migration


    Starting online migration of CT 300 to 192.168.5.45 Error: vzcpt module is not loaded on the source node Error: Can't continue online migration Error: vzcpt module is not loaded on the source node Error: Can't continue online migration This is a very easy fix, you just load the appropriate modules on the source and target node (althoughI don't know why the vzmigrate tool can't do that for the user on both ends):........
  • Convert HDD/Hard Drive Partition(s) into non-RAID into RAID 1 using existing data without data loss and without reformatting.


    Before we start I take no responsibility for this, you should have a backup and if you make a mistake during this process you could wipe out all of your data. So backup somewhere else before starting this as a precaution, or make sure it's data you could afford to lose. The RAID 1 Setup (Hardware Wise) I've already setup my 2 x 1TB (Seagate) drives with identical partitions, make sure your new hard drive (the empty one) is setup like your curr........
  • Linux EXT3 16GB-17GB maximum filesize issue solved/how to fix


    I have no idea why but mkfs.ext3 defaults to a patheticlly small blocksize of 1024 bytes/1KB (kilobyte). That means the maximum filesize is ONLY 16GB! With 2KB/2048 bytes you get a 256 GB maximum filesize, and with 4KB/4096 bytes you get 2TB! I finally noticed/paid attention to this after realizing that with rsync and scp that no file larger than 17GB could be transferred. I then realized it must be a file size limit on the partition. Here is what tune2fs tol........
  • email2fax and Asterisk to do eFaxing


    It's basically free bash shell script available from: http://wpkg.org/email2fax/index.php/Main_Page Make sure you have the required tools: libtiff ghostscript mpack/munpack Where you can e-mail your Asterisk box and it will fax it to the phone number in the subject line. The good news ends there, it is fairly undocumented and buggy. Take for example how the documentation mentions you can invoke from the com........
  • Picking an FTPD (vsftpd) Server in Linux Centos/Debian


    I decided on using yum to help me decide even though I normaly use proftpd I decided to see what else I could find. yum search ftp Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * rpmforge: ftp-stud.fht-esslingen.de * base: mirrors.netdna.com * updates: updates.interworx.info * addons: yum.singlehop.com * extras: mirrors.netdna.com rpmforge........
  • 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........
  • heartbeat is stopped for some reason


    heartbeat is stopped for some reason Anyway hnode2 was active and the services are running fine but I see heartbeat has been stopped somehow. Here is the last log I see of heartbeat: [quote:23c84415f5] Sep 9 17:15:32 hnode2 heartbeat: [16738]: info: MSG stats: 9/1762471 ms age 0 [pid16738/MST_CONTROL] Sep 9 17:15:32 hnode2 heartbeat: [16738]: info: cl_malloc stats: 716/51784021 152624/74519 [pid16738/MST_CONTROL] Sep 9 17:15:32........
  • Create/Enable SSL Certificates for Apache on Linux/Unix Systems eg. Redhat,Centos,Debian


    Shortcut/Easiest Way To Create A Self-Signed Key: openssl req -new -x509 -nodes -days 1530 -out server.crt -keyout server.key Using the above, you instantly create a self-signed certificate valid for 1530 days and you can simply skip to step #5.) below. If You Need a Real SSLCertificate (eg. Equifax/Openssl) then you need to create a CSR request (you'll need to follow Steps 1.) and 2.) in order to create the CSR. You then upload the CSR Certi........
  • Openvz "Container already locked" Error Message Solution/Fix


    I didn't find any useful information that actually fixed this. My VPS was in the "Running State" and I could not stop or restart it. I kept getting "Container already locked" no matter what Idid (I tried all the suggestions in the Google results for this error). Most of the suggestions were for Windows but I only use Linux. The other solutioins also said to restart the VZ service or even the entire hostnode and this was not acceptable to me........
  • GRUB "Error 2: Bad file or directory type" 0.97 won


    You can see the problem below, GRUB recognizes my hard drive and sees the partitions but cannot access them. This is from the GRUB boot disc I'm using. What happened is that I had some power issues causing this system's power to be interrupted several times and basically an on/off on/off situation. The system won't boot, I just get a flashing cursor and no message or error from GRUB. Obviously the problem is that my MBR seems corrupt or some other issue. My........
  • OpenVZ/Virtuozzo Enable Fuse in Container


    To enable Fuse to work inside a OpenVZ container it's very simple (although some people say it can't be done). Remember that on your HN(HostNode) for OpenVZ, Fuse must be installed and the module must be loaded for this to work. In addition remember that you need the Fuse package installed inside the container of course. vzctl set 2000 --devices c:10:229:rw --save vzctl exec 2000 mknod /dev/fuse c 10 229 The part that most people forget........
  • OCFS2 crash


    When trying to even cd or ls the mounted OCFS2 partition it crashes. Ithink this is a combination of VMWare Server's problem and the way I mounted and symlinked to it. More than anything this shows the problem and lack of forsight with VMWare, but also that OCFS2 is easily crashed if you do strange things. Output of /var/log/messages for OCFS2 Apr 10 15:57:45 localhost kernel: [84331.691258] Modules linked in: vmnet vmci vmmon ocfs2_stac........
  • Samba SMB Error - Server not using user level security and no password supplied. tree connect failed: NT_STATUS_WRONG_PASSWORD


    Server not using user level security and no password supplied. tree connect failed: NT_STATUS_WRONG_PASSWORD That happens when trying to use smbclient to connect to a share. The weird thing is that I can authnenticate just fine from Windows XP. It is partially my mistake, I forgot this share does have a password. I've tried authenticating with the correct user and also with "Guest" because this works in Windows. In Linux I ........
  • Configuring OCFS2 Clustered File System on Debian Based Linux including Ubuntu and Kubuntu


    There's a lot of information and guides on OCFS2 for RHELand Centos Linux but the package setup and configuration is slightly different and this has thrown some people off. Installing OC2FS You should install the following packages to get started: apt-get install ocfs2-tools ocfs2console Configure OC2FS In RHEL/Centos the main configuration file is located in /etc/sysconfig/o2cb However in Debian based Linux it is located........
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