Namespaces 10 - Connecting two network namespaces (ns1, ns2) - with two ports on a distributed OVS switch (openvswitch)

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 [1] NET namespace - Connecting two network namespaces (ns1, ns2) - with two ports on a distributed
                     OVS switch (openvswitch)
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     +------------------+                  +-------------------------------+                  +------------------+
     | ns1    veth1-ovs |=====ovs-port=====|              ovs0             |=====ovs-port=====| veth2-ovs    ns2 |
     +------------------+                  +-------------------------------+                  +------------------+
       namespace "ns1"                         host system (openvswitch)                        namespace "ns2"

    The first OVS port - an internal OVS port "veth1-ovs" is created on the OVS switch and given to namespace "ns1".
    The second OVS port - an internal OVS port "veth2-ovs" is created on the OVS switch and given to namespace "ns2".

    These test scenarios use RedHat Linux 7.3, which does carry the kernel module for Openvswitch, but
    no longer carries the user tools that administer openvswitch (ovs-vsctl). Those user tools are
    carried in other Redhat products such as Red Hat Openstack Platform and the like. At this point
    there is nothing for it but to install Openvswitch from source, see [1.0.X].

    [1.0.1] Installing the distributed switch Openvswitch successfully needs the tools to compile it and
            the libraries that Openvswitch uses.
    ----------------------------------------------------------------------------------------------------------------
    # yum install gcc make python-devel openssl-devel kernel-devel graphviz kernel-debug-devel autoconf automake \
      rpm-build redhat-rpm-config libtool checkpolicy selinux-policy-devel python-six
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    [1.0.2] - Create a directory to build the RPM package from source in, and download the current source package
              for Openvswitch.
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    # mkdir -p /root/rpmbuild/SOURCES
    # cd /root/rpmbuild/SOURCES
    # wget http://openvswitch.org/releases/openvswitch-2.6.1.tar.gz
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    [1.0.3] - Unpack the source package, compile it and build the RPM package
              The RPM packages for Openvswitch appear in "/root/rpmbuild/RPMS/x86_64/"
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    # cd /root/rpmbuild/SOURCES/
    # tar -xvf ./openvswitch-2.6.1.tar.gz
    # sed 's/openvswitch-kmod, //g' openvswitch-2.6.1/rhel/openvswitch.spec > openvswitch-2.6.1/rhel/openvswitch_no_kmod.spec
    # rpmbuild -bb --nocheck openvswitch-2.6.1/rhel/openvswitch_no_kmod.spec
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    [1.0.4] - Install the RPM package with Openvswitch
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    # cd /root/rpmbuild/RPMS/x86_64/
    # yum localinstall ./openvswitch-2.6.1-1.x86_64.rpm
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    [1.1] - Remove the network namespaces "ns1" and "ns2" (if they exist).
    [1.2] - Create two network (NET) namespaces, "ns1" and "ns2".
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    [1.1]# ip netns del ns1 &>/dev/null
    [1.1]# ip netns del ns2 &>/dev/null
    [1.2]# ip netns add ns1
    [1.2]# ip netns add ns2
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    [1.3] - On the host system, start Openvswitch and
    [1.3] - create a distributed (openvswitch) Ethernet switch/bridge named "ovs0".
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    [1.3]# /etc/init.d/openvswitch start
    [1.3]# ovs-vsctl add-br ovs0
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    [1.4]TERM1 - In network namespace "ns1", exec the command "bash".
    [1.5]TERM2 - In network namespace "ns2", exec the command "bash".
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    [1.4]TERM1# ip netns exec ns1 bash
    [1.5]TERM2# ip netns exec ns2 bash
    ----------------------------------------------------------------------------------------------------------------

    [1.6] - On the distributed switch "ovs0", create the internal port "veth1-ovs".
    [1.7] - Put the virtual Ethernet adapter "veth1-ovs" into network namespace "ns1".

    [1.8] - On the distributed switch "ovs0", create the internal port "veth2-ovs".
    [1.9] - Put the virtual Ethernet adapter "veth2-ovs" into network namespace "ns2".
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    [1.6]# ovs-vsctl add-port ovs0 veth1-ovs -- set Interface veth1-ovs type=internal
    [1.7]# ip link set veth1-ovs netns ns1

    [1.8]# ovs-vsctl add-port ovs0 veth2-ovs -- set Interface veth2-ovs type=internal
    [1.9]# ip link set veth2-ovs netns ns2
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    [1.10] - Bring the network adapter "veth1-ovs" up in namespace "ns1" and give it the address "10.0.0.1".
    [1.11] - Bring the network adapter "veth2-ovs" up in namespace "ns2" and give it the address "10.0.0.2".

    [1.12] - From network namespace "ns1", test that namespace "ns2" answers.
    [1.13] - From network namespace "ns2", test that namespace "ns1" answers.
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    [1.10]# ip netns exec ns1 ifconfig veth1-ovs 10.0.0.1/24 up
    [1.11]# ip netns exec ns2 ifconfig veth2-ovs 10.0.0.2/24 up

    [1.12]# ip netns exec ns1 ping 10.0.0.2
    [1.13]# ip netns exec ns2 ping 10.0.0.1
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    [1.14] - On the distributed switch "ovs0", show the port configuration information.
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    [1.14]# ovs-vsctl show
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    31dff9cb-870d-4093-915d-28dc71f8ac6e
        Bridge "ovs0"
            Port "ovs0"
                Interface "ovs0"
                    type: internal
            Port "veth1-ovs"
                Interface "veth1-ovs"
                    type: internal
            Port "veth2-ovs"
                Interface "veth2-ovs"
                    type: internal
        ovs_version: "2.6.1"
    ----------------------------------------------------------------------------------------------------------------

$ # ip -n ns1 addr add 10.0.0.1/24 dev veth1-ovs
$ # ip -n ns1 link set veth1-ovs up
$ # ip -n ns2 addr add 10.0.0.2/24 dev veth2-ovs
$ # ip -n ns2 link set veth2-ovs up