corosync died: Could not read cluster configuration Check cluster logs for details

Well, if you see this and you did nothing to your cluster other than freeing up some space, you may just find yourself seeing the error below,

Stopping cluster:
   Stopping dlm_controld... [  OK  ]
   Stopping fenced... [  OK  ]
   Stopping cman... [  OK  ]
   Unloading kernel modules... [  OK  ]
   Unmounting configfs... [  OK  ]
Starting cluster:
   Checking if cluster has been disabled at boot... [  OK  ]
   Checking Network Manager... [  OK  ]
   Global setup... [  OK  ]
   Loading kernel modules... [  OK  ]
   Mounting configfs... [  OK  ]
   Starting cman... corosync died: Could not read cluster configuration Check cluster logs for details

Google around and you get scary stuff like reinstalling the cluster and stuff like that. But what really works for me without jumping off the building was that the cluster logs in /var/log/cluster was deleted and causes the corosync to die. Hence, you might want to check your log is there before doing some fanciful work of redoing everything.


Repair Window Server 2012r2 in KVM – 0xc000000f

This is more like my issue which i give myself today. Hence, i better write out how to save my ass later on. Basically i have a Window Server 2012r2 in KVM and after i adjust the hard drive by expanding it, something bad happen and i get the following error

0xc000000f – The Boot Selection Failed Because A Required Device Is Inaccessible

Yeah, I can't restart my server. Hence, i downloaded Window Server 2012r2 iso and boot from it hoping that my server is able to repair and reboot again. I was wrong. It wasn't that easy. Lucky i manage to do it somehow, hence, here, i will be writing how i did it.

Repairing Window Server 2012r2 in KVM

The first thing you need to do is to attach the Window Server 2012r2 setup disc under the DVD drive,

Next head over to fedoraproject and download the virtio driver and also attach it to kvm.

Screen Shot 2016-06-04 at 3.02.05 AM

You should have something like the one shown above. Now boot from Windows Server 2012r2 as show below,

Screen Shot 2016-06-04 at 3.06.12 AM

Click on Repair Your Computer and you will see this

Screen Shot 2016-06-04 at 3.06.20 AM

Click on Troubleshoot and you will see this

Screen Shot 2016-06-04 at 3.06.26 AM

Click on System Recovery Image

Screen Shot 2016-06-04 at 3.06.52 AM

You will see a warning, ignore it and click Next

Screen Shot 2016-06-04 at 3.07.01 AM

Click on Install a driver

Screen Shot 2016-06-04 at 3.07.22 AM

Now, select the drive that has virtio driver on it and find a folder call viostor and select the file u see above. Then exit this and go to command prompt,

then key in the following command


and list out the volume and make sure you can see your hard disk here.

list volume

It will indicate the RAW volume, which is actually the NTFS partition and is responsible for the generation of boot error.

Screen Shot 2016-06-04 at 3.09.52 AM

Now our main target is to convert this RAW volume into NTFS partition. To do so, type the following command:

chkdsk /r /f f:

Once this command used, the main partition now generates the error β€œThe first NTFS boot sector is unreadable or corrupt.” But the good thing is that it actually repairs the second partition.

In this way RAW volume is converted into NTFS partition and the other errors involving indexes, master file table etc. are identified and repaired automatically. Reboot the machine and you should be able to access normally now. All fix!

Credit goes to the following,


and good luck guys!


Setup MongoDB 3.2 Geographical Replica Set in Ubuntu 15.10

Interestingly, i needed to setup a Replica Set on Ubuntu 15.10 for MongoDB 3.2 which is the latest Ubuntu and MongoDB version. This also serve as a tutorial for anyone who is interested in setting up a MongoDB Replica Set as well.

Import the public key used by the package management system.

Login to your server as root, we will need to import the public key use by the package manager for mongodb, just fire the following command,

sudo apt-key adv --keyserver hkp:// --recv 7F0CEB10

And we are good here.

Create a Source list file for MongoDB and Installation

Next, we need to add the source list for MongoDB. However, since MongoDB did not support 15.10 at this time, we will use debian ones

echo "deb wheezy/mongodb-org/3.0 main" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.0.list

Now, we will need to update the server and install mongodb

sudo apt-get update
sudo apt-get install -y mongodb-org

And after everything finished running, you should have your mongodb running.

sudo service mongod start

if no error is given, meaning your MongoDB has successfully installed.

Setup Replica Set

Now, assuming you did the above on 3 machines, you will need to setup each replica with the following steps,

head over to /etc/mongod.conf and replace your config with the one show below,

# mongod.conf

# for documentation of all options, see:

    dbPath: "/data/mongo"
    directoryPerDB: false
        enabled: true
    engine: "wiredTiger"
            cacheSizeGB: 1
            blockCompressor: snappy
    destination: file
    path: "/var/log/mongodb.log"
    logAppend: true
    logRotate: reopen
    timeStampFormat: iso8601-utc
  port: 27017

   oplogSizeMB: 500
   replSetName: dstTest

Next, create the folder for MongoDB data,

mkdir -p /data/mongo
chown -R mongodb:mongodb /data

Once you have done that, restart MongoDB and make sure there is no error.

sudo service mongod restart

Next we need to setup each replica in MongoDB.

Configure the servers to include in replica set

Assuming you have 3 machines, with the following hostname

Now, head over to the primary MongoDB server that you would like it to be primary (in my case, and enter to mongodb using the command below,


then paste the following

rs.reconfig({ _id : "testDB", members : [ {_id : 0, host : "", priority: 5}, {_id : 1, host : "", priority: 4}, {_id : 2, host : "", priority: 3 } ] })

take note of the priority i have given it and make sure this is one liner (yeah its messy but that's how i copy and paste it in one piece), then check your conf


and status at


and you got yourself a 3 location replica set of MongoDB!

***** UPDATE *****

Adding Security Authentication

If you want to add authentication into your setup, you will need to visit /etc/mongod.conf and add the following

  keyFile: /data/mongodb-keyfile

on all of your primary and secondary Mongodb server. The file will need to generate this way,

openssl rand -base64 741 > /data/mongodb-keyfile
chmod 600 mongodb-keyfile

This is to ensure all replica set can communicate with each other. Once you have generated the file above on the primary MongoDB server, copy the same file to other secondary server and update the /etc/mongod.conf on each secondary server along with it.


How To Install Aide Intrusion Detection System on Ubuntu

Aide stands for Advanced Intrusion Detection Environment which is one of the most popular tools for monitoring changes to a Unix or Linux system. Here i will list out how i am going to set this baby up on some of my server to secure on system.

Updating and Installing Aide

sudo apt-get update -y

Once you have update your repo, simply install Aide using the following command

sudo apt-get install aide

And aide is installed in your machine!

Configuring and Test out Aide

Next we are going to configure this baby. Initial the database with the command below,

sudo aideinit

It will take a while and once you have initial the database, Verify that the new aide database has been created

cd /var/lib/aide
ls -lt

And you should see something like this

AIDE 0.16a2-19-g16ed855 initialized AIDE database at /var/lib/aide/
Start timestamp: 2016-05-12 10:17:20 -0400
Verbose level: 6

Number of entries:	66800

The attributes of the (uncompressed) database(s):

  RMD160   : BOdplDoXDH0ws73WkoYe11+WIhM=
  TIGER    : tJ8xmXCDo9N9e8cJZBuqQSW/yl/ArSnJ
  SHA256   : E+Pc3ae0PDDxfRV9PcZZ8Fq+NsJZBLbo
  SHA512   : WHHce2bdDPzP1NgMSr9afReWcIvGbW+p
  CRC32    : OqKLPA==
  HAVAL    : zT+SY0Ee5SuFaXb7Kjo3gU7NpnH+QIyA
  GOST     : 4cW9q/3KpRawsNsRc2HtdjGgF70fsaI5

End timestamp: 2016-05-12 10:24:58 -0400 (run time: 7m 38s)

Move the new file to the new database using the following command,

mv /var/lib/aide/ /var/lib/aide/aide.db

Now, let's test this baby out with the following command,

aide.wrapper --check

and you will get something like this

root@mongodb-pk:~# aide.wrapper --check
AIDE 0.16a2-19-g16ed855 found differences between database and filesystem!!
Start timestamp: 2016-05-12 10:29:51 -0400
Verbose level: 6

  Total number of entries:	66801
  Added entries:		1
  Removed entries:		1
  Changed entries:		3

Added entries:

f++++++++++++++++: /var/lib/aide/aide.db

Removed entries:

f----------------: /var/lib/aide/

Changed entries:

d =.... mc.. .. .: /var/lib/mongodb/
f >b... mc..C.. .: /var/lib/mongodb/
f >.... mci.C.. .: /var/lib/mongodb/

Detailed information about changes:

Directory: /var/lib/mongodb/
  Mtime    : 2016-05-12 10:24:39 -0400        | 2016-05-12 10:36:39 -0400
  Ctime    : 2016-05-12 10:24:39 -0400        | 2016-05-12 10:36:39 -0400

File: /var/lib/mongodb/
  Size     : 361980                           | 372957
  Bcount   : 720                              | 744
  Mtime    : 2016-05-12 10:22:08 -0400        | 2016-05-12 10:32:08 -0400
  Ctime    : 2016-05-12 10:22:08 -0400        | 2016-05-12 10:32:08 -0400
  RMD160   : czpo/fk+iRIEKUBjlc2+wELg/Wo=     | wEQV9cj/KyiGQmfGSLbzo9B44Gs=
  TIGER    : 2wLpFPWq3lxfxXyHpAMkVXUjDtZ08W8z | x8IbKbindr6NVwNbaUt0J5jWq9Y1cWmv
  SHA256   : lVRtuDTLDD7DYajbBEYoMSPpdrtxdJNA | 3J4B2ToLfGmBbHOQas/hKGj8HXe4zihW
             rxL5xH8A0kA=                     | 0OLKtXC4fqo=
  SHA512   : axlztAMc56xIGz7JnsOq8dAgZfCLmT83 | 49Fex6rPE24SnoOaLc+T/hIiTLEEyOmk
             gFZS6MB2zmT5aPxK4FmOSnEC9W5mtUNJ | YGeLF1W/fxZuRYk3FuwgpFlKA2qrmi2f
             AIaoa5bK736BAXwMcsA+NA==         | xNij3UG21mAiX+Tx2pRw+A==
  CRC32    : drkWXw==                         | rtCgKQ==
  HAVAL    : SR2yfai80zpN2Xw+8sUFSM/kTQBGAHsl | xIk6ByhAZN5C2eU2bTJzZ0oZcJeqsIiz
             71FSIVFT4qA=                     | AMbC0DPcNhg=
  GOST     : bE/NiblzIQRPzFx8jVymvvkEA+NO6on0 | txFhbK566EUxlQk6c36TfqgvYBttntcm
             k3XlP3vO2LA=                     | qyMIxjG3zK8=

File: /var/lib/mongodb/
  Size     : 5279                             | 5397
  Mtime    : 2016-05-12 10:24:39 -0400        | 2016-05-12 10:36:39 -0400
  Ctime    : 2016-05-12 10:24:39 -0400        | 2016-05-12 10:36:39 -0400
  Inode    : 1180042                          | 1179903
  RMD160   : Uch+G7OlOobiM/VjjdNHYSdCZUY=     | OnSReGX+lqQuCQURBBxkfHC9U5o=
  TIGER    : bB0QmZYYNl2SKSfz4MlNrpwYKwCS3Evf | ktNDR+97gTAK7catLGoOhEFJu6IfQZwi
  SHA256   : h0s1leYNb7/RxTi86z+nHhe7DChFJtSo | KIlG5ePVgwG/+DopSTPHo6VqnGzdnQMj
             TUZXyOwKKYw=                     | m97NR3Gifhk=
  SHA512   : 8PrN5C6RJgYHIuM7DjL3vjx9/5fRbnsr | QLXQngP8ouoc8bvs580De+Vh7bGR0Lq8
             MDpk+PcTAxLV3AUbkWP9Xq0hTzro7mlM | +2tXCfVed02e1DVRgxeG3LbKxqhofP76
             nT96+O95DnPZRmuD5OAPZA==         | 6Mz99D/w7u9eabdbsYmmOw==
  CRC32    : sTX43A==                         | Ta6Udw==
  HAVAL    : ZDpLBirCqbUqz/jym+FFjv2IvY9T4k+g | qTpVXVypYnzMGQZF4SMw7Wjg/jKkptpw
             hhcWR0kK/ZE=                     | PEqS+lI8g84=
  GOST     : 7yJZnGdeAM8slovcFTD0Ftcec5KT8weQ | gVW46Bk3upRekyxDI5sPP6N1xk7b6gX5
             yPYlQqSMkf4=                     | CJTybT2VVKQ=

The attributes of the (uncompressed) database(s):

  RMD160   : BOdplDoXDH0ws73WkoYe11+WIhM=
  TIGER    : tJ8xmXCDo9N9e8cJZBuqQSW/yl/ArSnJ
  SHA256   : E+Pc3ae0PDDxfRV9PcZZ8Fq+NsJZBLbo
  SHA512   : WHHce2bdDPzP1NgMSr9afReWcIvGbW+p
  CRC32    : OqKLPA==
  HAVAL    : zT+SY0Ee5SuFaXb7Kjo3gU7NpnH+QIyA
  GOST     : 4cW9q/3KpRawsNsRc2HtdjGgF70fsaI5

End timestamp: 2016-05-12 10:37:13 -0400 (run time: 7m 22s)

see the file that we just added and updated? Yeah, that's the one that its reporting.

Crontab Aide

Now we dont want to do this every single day manually, so let's setup a crontab.


with the following code

#! /bin/sh
MYDATE=`date +%Y-%m-%d`
/bin/echo "Aide check !! `date`" > /tmp/$MYFILENAME
/usr/bin/aide.wrapper --check > /tmp/myAide.txt
/bin/cat /tmp/myAide.txt|/bin/grep -v failed >> /tmp/$MYFILENAME
/bin/echo "**************************************" >> /tmp/$MYFILENAME
/usr/bin/tail -20 /tmp/myAide.txt >> /tmp/$MYFILENAME
/bin/echo "****************DONE******************" >> /tmp/$MYFILENAME
/usr/bin/mail -s"$MYFILENAME `date`" < /tmp/$MYFILENAME

now make it executable

chmod +x

open up crontab

crontab -e

add the following crontab into it

06 01 * * 0-6 /root/

And we are good to go! Simple as that!


Setup NFS Server on LXC in Proxmox

Quick tutorial on how i setup NFS server on Proxmox using LXC rather than the old OpenVZ. Before i began writing out my old tutorial on NFS, you can take a look at the instruction on OpenVZ NFS which is exactly the same. I will write out a quick one here.

NFS Server on LXC

Do the following instruction to install NFS server (i'm using Centos btw)

yum install nfs* -y
service rpcbind start
chkconfig rpcbind on
service nfs start
chkconfig nfs on
Starting NFS services:                                     [  OK  ]
Starting NFS quotas:                                       [  OK  ]
Starting NFS mountd:                                       [  OK  ]
Starting NFS daemon: rpc.nfsd: Unable to access /proc/fs/nfsd errno 2 (No such file or directory).
Please try, as root, 'mount -t nfsd nfsd /proc/fs/nfsd' and then restart rpc.nfsd to correct the problem

Failure is part of the plan. Now, assuming your LXC is on 101, you will go to /etc/pve/lxc/101.conf and add the following line

arch: amd64
cpulimit: 4
cpuunits: 1024
memory: 4000
net0: bridge=vmbr2,gw=,hwaddr=32:36:30:61:61:34,ip=,name=eth0,type=veth
onboot: 1
ostype: centos
rootfs: local:101/vm-101-disk-1.raw,size=1000G
searchdomain: localhost
swap: 512
lxc.aa_profile: unconfined

I will show you what i added, which is

lxc.aa_profile: unconfined

and also remember to add the line to /var/lib/lxc/101/config


remember to reboot your LXC or else it won't work.

Now, in your LXC, open the file /etc/exports

/mnt/nfs     *(rw,no_root_squash,no_subtree_check,fsid=0)

and add the above line. remember to create the folder /mnt/nfs

Enable Port on Firewall

Enable the following in iptables

-A PREROUTING -d -i vmbr0 -p tcp -m tcp --dport 2925 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p tcp -m tcp --dport 32803 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p tcp -m tcp --dport 892 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p tcp -m tcp --dport 662 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p tcp -m tcp --dport 2049 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p tcp -m tcp --dport 111 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p udp -m udp --dport 892 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p udp -m udp --dport 662 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p udp -m udp --dport 111 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p udp -m udp --dport 2049 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p udp -m udp --dport 32769 -j DNAT --to-destination
-A PREROUTING -d -i vmbr1 -p tcp -m tcp --dport 8000 -j DNAT --to-destination

where is public ip and is lxc ip address.

Configure NFS

Head over to /etc/sysconfig/nfs and update the following

# Define which protocol versions mountd
# will advertise. The values are "no" or "yes"
# with yes being the default
# Path to remote quota server. See rquotad(8)
# Port rquotad should listen on.
# Optinal options passed to rquotad
# Optional arguments passed to in-kernel lockd
# TCP port rpc.lockd should listen on.
# UDP port rpc.lockd should listen on.
# Optional arguments passed to rpc.nfsd. See rpc.nfsd(8)
# Turn off v2 and v3 protocol support
# Turn off v4 protocol support
# Number of nfs server processes to be started.
# The default is 8.
# Stop the nfsd module from being pre-loaded
# Set V4 and NLM grace periods in seconds
# Warning, NFSD_V4_GRACE should not be less than
# NFSD_V4_LEASE was on the previous boot.
# To make NFSD_V4_GRACE shorter, with active v4 clients,
# first make NFSD_V4_LEASE shorter, then restart server.
# This will make the clients aware of the new value.
# Then NFSD_V4_GRACE can be decreased with another restart.
# When there are no active clients, changing these values
# can be done in a single server restart.
# Optional arguments passed to rpc.mountd. See rpc.mountd(8)
# Port rpc.mountd should listen on.
# Optional arguments passed to rpc.statd. See rpc.statd(8)
# Port rpc.statd should listen on.
# Outgoing port statd should used. The default is port
# is random
# Specify callout program
# Optional arguments passed to rpc.idmapd. See rpc.idmapd(8)
# Set to turn on Secure NFS mounts.
# Optional arguments passed to rpc.gssd. See rpc.gssd(8)
# Optional arguments passed to rpc.svcgssd. See rpc.svcgssd(8)
# To enable RDMA support on the server by setting this to
# the port the server should listen on

once you have done all the above, restart your host machine so you are clean and good to go.