Reduce resource consumption and clone in seconds your oracle virtual environment on your laptop using linux containers and btrfs

Last week I wanted to create a new oracle virtual machine on my Laptop and I discovered that the disk space on my SSD device was more or less exhausted. Then I looked for a solution to minimize the disk usage of my oracle virtual machines.

I find a way to achieve my need based on those technologies:

  • Linux Containers: a lightweight virtualization solution for Linux.
  • btrfs file system: a file system that allows to create snapshots almost instantly and consume virtually no additional disk space as a snapshot and the original it was taken from initially share all of the same data blocks.

In this post I will show how I create an oracle environment on my laptop with those technologies and how we can clone a container, an ORACLE_HOME and a database in a few seconds with initially no additional disk space.

Note:  The goal is to create a “test” environment on your laptop. I would not suggest to follow this installation process on a “real” system 😉

PREPARATION PHASE

Step 1: let’s create a OEL 6.5 virtual machine (named lxc) using virtualbox. This virtual machine will host our Linux containers, oracle software and databases.

Step 2: Install lxc and btrfs into the virtual machine created into step 1.

[root@lxc ~]# yum install btrfs-progs
[root@lxc ~]# yum install lxc
[root@lxc ~]# service cgconfig start
[root@lxc ~]# chkconfig cgconfig on
[root@lxc ~]# service libvirtd start
[root@lxc ~]# chkconfig libvirtd on

Step 3: Add a btrfs file system into the virtual machine (This file system will receive the oracle software and databases). To do so, add a disk to your virtualbox machine created in step 1, start the machine and launch the fs creation:

[root@lxc ~]# mkfs.btrfs /dev/sdb
[root@lxc ~]# mkdir /btrfs
[root@lxc ~]# mount /dev/sdb /btrfs
[root@lxc ~]# chown oracle:dba /btrfs
[root@lxc ~]# blkid /dev/sdb
/dev/sdb: UUID="3f6f7b51-7662-4d81-9a29-195e167e54ff" UUID_SUB="1d79e0d0-933d-4c65-9939-9614375da5e1" TYPE="btrfs"
Retrieve the UUID and put it into the fstab
[root@lxc ~]# cat >> /etc/fstab << EOF
UUID=3f6f7b51-7662-4d81-9a29-195e167e54ff /btrfs btrfs    defaults   0 0
EOF

Step 4: Add a btrfs file system into the virtual machine (This file system will receive the linux containers). To do so, add a disk to your virtualbox machine created in step 1, start the machine and launch the fs creation:

[root@lxc ~]# mkfs.btrfs /dev/sdc
[root@lxc ~]# mkdir /container
[root@lxc ~]# mount /dev/sdc /container
[root@lxc ~]# blkid /dev/sdc
/dev/sdc: UUID="8a565bfd-2deb-4d02-bd91-a81c4cc9eb54" UUID_SUB="44cb0a14-afc5-48eb-bc60-4c24b9b02ab1" TYPE="btrfs"
Retrieve the UUID and put it into the fstab
[root@lxc ~]# cat  >> /etc/fstab << EOF
UUID=8a565bfd-2deb-4d02-bd91-a81c4cc9eb54 /container btrfs    defaults   0 0
EOF

Step 5: Create btrfs subvolume for the database software and databases.

[root@lxc ~]# btrfs subvolume create /btrfs/u01
Create subvolume '/btrfs/u01'
[root@lxc ~]# btrfs subvolume create /btrfs/databases
Create subvolume '/btrfs/databases'
[root@lxc ~]# chown oracle:dba /btrfs/u01
[root@lxc ~]# chown oracle:dba /btrfs/databases

Step 6: add the hostname into /etc/hosts

[root@lxc btrfs]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4 lxc
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

and Install the 12cR1 database software with:

Oracle Base: /btrfs/u01
Software location: /btrfs/u01/product/12.1.0/dbhome_1
Inventory directory: /btrfs/u01/oraInventory
oraInventory Group Name: dba

Step 7: Create a simple database with datafiles, redologs and controlfile located into the /btrfs/databases folder.

Step 8: Create a linux container (using oracle template) that will be the source of all our new containers.

lxc-create --name cont_source -B btrfs --template oracle -- --url http://public-yum.oracle.com -R 6.latest -r "perl sudo oracle-rdbms-server-12cR1-preinstall"

Here we are: we are now ready to clone all of this into a new linux container in seconds without any additional disk usage.

CLONING PHASE

First, let’s take a picture of the current disk usage:

[root@lxc ~]# df -h 
Filesystem                  Size  Used Avail Use% Mounted on
/dev/mapper/vg_lxc-lv_root   45G  3.1G   40G   8% /
tmpfs                       2.0G     0  2.0G   0% /dev/shm
/dev/sda1                   477M   55M  398M  13% /boot
/dev/sdb                     50G  6.4G   42G  14% /btrfs
/dev/sdc                     50G  1.1G   48G   3% /container

Clone step 1:  Add into  /etc/security/limits.conf  (If not, you won’t be able to su – oracle into the linux containers)

*   soft   nofile    1024
*   hard   nofile    65536
*   soft   nproc    2047
*   hard   nproc    16384
*   soft   stack    10240
*   hard   stack    32768

and reboot the virtual machine created into step 1.

Clone step 2:  clone the linux container created during step 8 to a new one named for example dbhost1.

[root@lxc oradata]# time lxc-clone -s -t btrfs -o cont_source -n dbhost1
Tweaking configuration
Copying rootfs...
Create a snapshot of '/container/cont_source/rootfs' in '/container/dbhost1/rootfs'
Updating rootfs...
'dbhost1' created

real    0m0.716s
user    0m0.023s
sys     0m0.029s

Clone step 3: clone the database software.

[root@lxc oradata]# time btrfs su snapshot /btrfs/u01 /btrfs/u01_dbhost1
Create a snapshot of '/btrfs/u01' in '/btrfs/u01_dbhost1'

real    0m0.038s
user    0m0.000s
sys     0m0.006s

Clone step 4: clone the database (shutdown immediate before)

[root@lxc oradata]# time btrfs su snapshot /btrfs/databases /btrfs/databases_dbhost1
Create a snapshot of '/btrfs/databases' in '/btrfs/databases_dbhost1'

real    0m0.041s
user    0m0.002s
sys     0m0.006s

Clone step 5: Link the new container to this database software and database clones. Edit /container/dbhost1/config and put:

lxc.mount.entry=/btrfs/u01_dbhost1 /container/dbhost1/rootfs/btrfs/u01 none rw,bind 0 0
lxc.mount.entry=/btrfs/databases_dbhost1 /container/dbhost1/rootfs/btrfs/databases none rw,bind 0 0

Clone step 6: Copy dbhome, oraenv and coraenv and start the new container dbhost1

[root@lxc ~]# cp -p /usr/local/bin/coraenv /usr/local/bin/dbhome /usr/local/bin/oraenv /container/dbhost1/rootfs/usr/local/bin
[root@lxc oradata]# mkdir -p /container/dbhost1/rootfs/btrfs/u01
[root@lxc oradata]# mkdir -p /container/dbhost1/rootfs/btrfs/databases
[root@lxc oradata]# lxc-start -n dbhost1

Clone step 7: connect to the new container (default password for root is root), create the oratab, and start the database.

[root@lxc ~]# lxc-console -n dbhost1
[root@dbhost1 ~]# su  - oracle
[oracle@dbhost1 dbs]$ . oraenv
ORACLE_SID = [BDTDB] ? 
The Oracle base remains unchanged with value /btrfs/u01
[oracle@dbhost1 dbs]$ echo "startup" | sqlplus / as sysdba

SQL*Plus: Release 12.1.0.1.0 Production on Fri Apr 25 08:01:52 2014

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> ORACLE instance started.

Total System Global Area 1570009088 bytes
Fixed Size                  2288776 bytes
Variable Size             905970552 bytes
Database Buffers          654311424 bytes
Redo Buffers                7438336 bytes
Database mounted.
Database opened.

Check the disk usage on our virtual machine created into step 1:

[root@lxc ~]# df -h
Filesystem                  Size  Used Avail Use% Mounted on
/dev/mapper/vg_lxc-lv_root   45G  3.1G   40G   8% /
tmpfs                       2.0G     0  2.0G   0% /dev/shm
/dev/sda1                   477M   55M  398M  13% /boot
/dev/sdb                     50G  6.4G   42G  14% /btrfs
/dev/sdc                     50G  1.1G   48G   3% /container

Et voila 😉 we created a new linux container, a new database home and a new database with initially no additional disk space.

Remarks:

  • Jason Arneil did a demo on Linux containers here.
  • Ludovico Caldara also shows how to save disk space when building a RAC with virtualbox linked clones.
  • If you are interested in how oracle databases/rac and lxc can work together, I suggest to read Alvaro Miranda’s stuff here (I mainly took my inspiration from his blog).
  • Ofir Manor describes another Linux container use case related to Hadoop cluster here.
  • Cloning the database software as I did here is not the “right” way (See MOS Doc ID 1154613.1). But this suits me fine for my laptop environment.

Conclusion:

We can create a new container, a new ORACLE_HOME and a new database, reducing resource consumption (specially disk) on our laptop in a few seconds.

Again: I would not suggest to use all of this on a “real” system. But for a test environment on a laptop it sound goods to me.

I hope you will save some disk space on your laptop thanks to this ;-).

Advertisements

2 thoughts on “Reduce resource consumption and clone in seconds your oracle virtual environment on your laptop using linux containers and btrfs

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s