Oracle Linux Container LXC 7.3 on Oracle Linux 7.3

This article explains how to create a Linux Containers 7.3  LXC on Oracle Linux 7.x, while creating an interface network as a bridge with a dedicated network address.

Plan:

1. Install the pre-requis LXC container:
2. Creation of Oracle Linux container 7u3.
3. Set up a static IP address for Linux Container:

1. Install the pre-requis:

We have as a host, ORACLE Linux 7.3

# cat /etc/oracle-release
Oracle Linux Server release 7.3

# uname -a
Linux ol7-lxc.wadhahdaouehi.tn 3.8.13-118.16.3.el7uek.x86_64 #2 SMP Wed Feb 8 17:43:34 PST 2017 x86_64 x86_64 x86_64 GNU/Linux

a. Install the dedicated packages of the Linux containers.

Note: If  you want to Create the containers LXC on a File system BTRFS, then install the package btrfs-progs.

# yum install btrfs-progs lxc -y

Note: If you want to Create the containers LXC on a File system like XFS, then just install the package LXC because the File system XFS is built in Oracle Linux 7.x

# yum install lxc -y

b. Creation of the Filesystem container XFS.

Note: We can create btrfs file system on the disk and to use his feautures on cloning existing LXC container, but in my tutorial, I am going to use the filesystem XFS.

# fdisk /dev/sdb
# mkfs.xfs /dev/sdb1
# mount /dev/sdb1 /container

c. Sheck the Oracle Linux container templates:

The templates are located as script under the folder: /usr/share/lxc/templates

# ls /usr/share/lxc/templates
lxc-alpine     lxc-busybox  lxc-debian    lxc-gentoo        lxc-oracle  lxc-ubuntu
lxc-altlinux   lxc-centos   lxc-download  lxc-openmandriva  lxc-plamo   lxc-ubuntu-cloud
lxc-archlinux  lxc-cirros   lxc-fedora    lxc-opensuse      lxc-sshd

2. Creation of Oracle Linux container LXC 7u3:

Linux container creation requires the yum repository be available. I am going to use the public YUM repository.

• container name:  ol7u3.wadhahdaouehi.th
• template name: -t oracle
• release name: –release 7.3

# lxc-create -n ol7u3.wadhahdaouehi.tn -t oracle -- --release=7.3
..........
Complete!
Rebuilding rpm database
Patching container rootfs /container/ol7u3.wadhahdaouehi.tn/rootfs for Oracle Linux 7.3
Configuring container for Oracle Linux 7.3
Added container user:oracle password:oracle
Added container user:root password:root
Container : /container/ol7u3.wadhahdaouehi.tn/rootfs
Config    : /container/ol7u3.wadhahdaouehi.tn/config
Network   : eth0 (veth
veth) on lxcbr0

Note: After the creation of the Oracle Linux template the password of the user root is root and the user oracle is oracle as a password.

a. Verify the Configuration file of our container:

#cat /container/ol7u3.wadhahdaouehi.tn/config
# Template used to create this container: /usr/share/lxc/templates/lxc-oracle
# Parameters passed to the template: --release=7.3
# For additional config options, please look at lxc.container.conf(5)
lxc.network.type = veth
lxc.network.link = lxcbr0
lxc.network.flags = up
lxc.network.hwaddr = 00:16:3e:06:92:09
lxc.rootfs = /container/ol7u3.wadhahdaouehi.tn/rootfs
# Common configuration
lxc.include = /usr/share/lxc/config/oracle.common.conf
# Container configuration for Oracle Linux 7.3
lxc.arch = x86_64
lxc.utsname = ol7u3.wadhahdaouehi.tn
lxc.cap.drop = sys_resource
# Networking
lxc.network.name = eth0
lxc.network.mtu = 1500

 

b. Start / stop the container:

The option –name or -n to specify the container name.

# lxc-start --name ol7u3.wadhahdaouehi.tn
# lxc-stop --name  ol7u3.wadhahdaouehi.tn
# lxc-autostart -n ol7u3.wadhahdaouehi.tn

c. Connect to the container:

Method 1: Using the tool lxc-attach

# lxc-attach  -n ol7u3.wadhahdaouehi.tn

Method 2: Using the SSH connection after configuring the network, check next step.

3.  Set up a static IP address for Linux Container:

Note:  lxcbr0 – network bridge which was created automatically when the lxc tools have been installed.

a. I have chaged the bridge ip address to 192.168.20.1 on /etc/sysconfig/lxc-net

#grep ^LXC /etc/sysconfig/lxc-net
LXC_BRIDGE="lxcbr0"
LXC_ADDR="192.168.20.1"
LXC_NETMASK="255.255.255.0"
LXC_NETWORK="192.168.20.0/24"

b. Change the configuration file of the container: /container/ol7u3.wadhahdaouehi.tn/config

# Networking
lxc.network.type = veth
lxc.network.link = lxcbr0
lxc.network.flags = up
lxc.network.name = eth0
lxc.network.hwaddr = 00:16:3e:3b:b8:50
lxc.network.mtu = 1500
lxc.network.ipv4 = 192.168.20.201/24

c. Adding an other bridge interface lxcbr1:

# brctl addbr lxcbr1
# ifconfig lxcbr1 172.16.20.1/24
# ifconfig lxcbr1
lxcbr1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.16.20.1  netmask 255.255.255.0  broadcast 172.16.20.255
        inet6 fe80::a80d:ceff:feb9:f310  prefixlen 64  scopeid 0x20<link>
        ether aa:0d:ce:b9:f3:10  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 19  bytes 2957 (2.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Conclusion:

Creation of Oracle Linux 7.x container on the host Oracle Linux 7.3 and configuring the network connection.