Monday, 15 September 2014

Last post we have gone through some basic of Network administration, In this post we will be targeting some Advance features of Network administrations as like Link Aggregation, IPMP (IP Multipathing) features. Before going in deep we can see some basic concept of networking.

Basic Concepts :
  • Bandwidth : Bandwidth is bit rate for sending and receiving data over the network.
  • Failover     : Capability to have a backup component for the one becomes unavailable.
  • Load balancing : Distribution of workload to achieve best utilization.   
Link Aggregation:
Link Aggregation is combination of two or three physical interface on the system which are consider as a single logical unit (aggr) that provides best bandwidth, automatic fail over features, load balancing and redundancy benefits. Link Aggregation's Link should be in same Speed and same mode. We can administrate the link aggregation with using dladm command by adding, modifying, deleting links.

Before starting the aggregation, we have to make it sure physical interface should be have same mode as full-duplex  and same speed. By executing dladm show-link 

Creating aggregartion link with using two interface net1 and net2
root@unixrock:~# dladm create-aggr -l net1 -l net2 aggr0
root@unixrock:~#
root@unixrock:~# dladm show-link
LINK                CLASS     MTU    STATE    OVER
net0                phys      1500   up       --
net1                phys      1500   up       --
net3                phys      1500   up       --
net2                phys      1500   up       --
aggr0               aggr      1500   up       net1 net2
root@unixrock:~#
root@unixrock:~# dladm show-aggr
LINK              MODE  POLICY   ADDRPOLICY           LACPACTIVITY LACPTIMER
aggr0             trunk L4       auto                 off          short
root@unixrock:~#
To Add a another Link (net3) to an Aggregation (aggr0)
root@unixrock:~# dladm add-aggr -l net3 aggr0
root@unixrock:~# dladm show-link
LINK                CLASS     MTU    STATE    OVER
net0                phys      1500   up       --
net1                phys      1500   up       --
net3                phys      1500   up       --
net2                phys      1500   up       --
aggr0               aggr      1500   up       net1 net2 net3
root@unixrock:~#
To assigning IP to the aggregation link
root@unixrock:~# ipadm create-addr -T static -a 192.168.113.142 aggr0
ipadm: cannot create address: No such interface
root@unixrock:~#
Opps......getting error says that No such interface, that means we have to probe the interface first
root@unixrock:~# ipadm create-ip aggr0
root@unixrock:~# ipadm create-addr -T static -a 192.168.113.142 aggr0
aggr0/v4
root@unixrock:~#
Yes...we have done the aggr0 aggregation link with using net1 net2 net3 physical link and assigned Ip address too.
root@unixrock:~# dladm show-link
LINK                CLASS     MTU    STATE    OVER
net0                phys      1500   up       --
net1                phys      1500   up       --
net3                phys      1500   up       --
net2                phys      1500   up       --
aggr0               aggr      1500   up       net1 net2 net3
root@unixrock:~#
root@unixrock:~# ipadm show-addr
ADDROBJ           TYPE     STATE        ADDR
lo0/v4            static   ok           127.0.0.1/8
net0/v4test       static   ok           192.168.113.139/24
aggr0/v4          static   ok           192.168.113.142/24
lo0/v6            static   ok           ::1/128
root@unixrock:~#
To delete/remove the link from an Aggregation link
root@unixrock:~# dladm show-link
LINK                CLASS     MTU    STATE    OVER
net0                phys      1500   up       --
net1                phys      1500   up       --
net3                phys      1500   up       --
net2                phys      1500   up       --
aggr0               aggr      1500   up       net1 net2 net3
root@unixrock:~# dladm remove-aggr -l net3 aggr0
root@unixrock:~#
root@unixrock:~# dladm show-link
LINK                CLASS     MTU    STATE    OVER
net0                phys      1500   up       --
net1                phys      1500   up       --
net3                phys      1500   unknown  --
net2                phys      1500   up       --
aggr0               aggr      1500   up       net1 net2
root@unixrock:~#
IP Multipathing (IPMP)
IP Multipathing (IPMP) provides physical interface failure detection, Load balancing of packets, and transparent redundancy  features. IPMP which makes possible to assign the IP address to a group of network interface. if any one of the interface fails, the group can bind the IP address to another interface from the same IPMP group as transparent redundancy. IPMP can be configured for both IPv4 and IPv6. IPMP group will come up with ACTIVE - ACTIVE and ACTIVE- STANDBY
Advantage of IPMP
  • Fault tolerance
  • Spreading the load
  • Increased bandwidth
  • Transparent redundancy
  • Works even if its different switches
Components of IPMP
  • IPMP daemon : in.mapthd
  • IPMP service : svc:/network/ipmp:default
  • IPMP conf file : /etc/default/mpathd
  • IPMP Commands : ipadm, ipmpstat
Let we start Creating an IPMP group and Adding IP address to an IPMP group and Deleting and disable the IPMP group.
Creating ipmp0 group with using "ipadm create-ipmp" command
root@unixrock:/# 
root@unixrock:/# ipadm create-ip net1
root@unixrock:/# ipadm create-ip net2
root@unixrock:/# ipadm create-ip net3
root@unixrock:/# ipadm create-ipmp ipmp0
root@unixrock:/# ipadm add-ipmp -i net1 -i net3 ipmp0
root@unixrock:/# ipmpstat -g
GROUP       GROUPNAME   STATE     FDT       INTERFACES
ipmp0       ipmp0       ok        --        net3 net1
root@unixrock:/#
Assigning IP to that ipmp0 group
root@unixrock:~# ipadm create-addr -T static -a 192.168.113.145 ipmp0/v4addr1
root@unixrock:~# ipadm create-addr -T static -a 192.168.113.146 ipmp0/v4addr2
root@unixrock:~# ipadm show-addr
ADDROBJ           TYPE     STATE        ADDR
lo0/v4            static   ok           127.0.0.1/8
net0/v4test       static   ok           192.168.113.139/24
ipmp0/v4addr1     static   ok           192.168.113.145/24
ipmp0/v4addr2     static   ok           192.168.113.146/24
lo0/v6            static   ok           ::1/128
root@unixrock:~#
Remove the interface from IPMP group
root@unixrock:~# ipmpstat -g
GROUP       GROUPNAME   STATE     FDT       INTERFACES
ipmp0       ipmp0       ok        --        net1 net3
root@unixrock:~#
root@unixrock:~# ipadm remove-ipmp -i net1 ipmp0
root@unixrock:~# ipmpstat -g
GROUP       GROUPNAME   STATE     FDT       INTERFACES
ipmp0       ipmp0       ok        --        net3 
root@unixrock:~#
Adding one Interface to the IPMP group
root@unixrock:~# ipmpstat -g
GROUP       GROUPNAME   STATE     FDT       INTERFACES
ipmp0       ipmp0       ok        --        net3
root@unixrock:~# ipadm add-ipmp -i net2 ipmp0
root@unixrock:~# ipmpstat -g
GROUP       GROUPNAME   STATE     FDT       INTERFACES
ipmp0       ipmp0       ok        --        net2 net3
root@unixrock:~#
To disable an IPMP group
root@unixrock:~# ipadm disable-if -t ipmp0
root@unixrock:~# ipmpstat -g
root@unixrock:~# ipadm show-addr
ADDROBJ           TYPE     STATE        ADDR
lo0/v4            static   ok           127.0.0.1/8
net0/v4test       static   ok           192.168.113.139/24
lo0/v6            static   ok           ::1/128
ipmp0/v4addr1     static   disabled     192.168.113.145
ipmp0/v4addr2     static   disabled     192.168.113.146
root@unixrock:~#
To delete the IPMP group
root@unixrock:~# ipadm delete-ipmp ipmp0
root@unixrock:~# ipadm show-addr
ADDROBJ           TYPE     STATE        ADDR
lo0/v4            static   ok           127.0.0.1/8
net0/v4test       static   ok           192.168.113.139/24
lo0/v6            static   ok           ::1/128
root@unixrock:~#
Encountered some issues and fixes
ERROR : ipadm: cannot delete IPMP interface ipmp0: IPMP group is not empty
root@unixrock:~# ipadm delete-ipmp ipmp0
ipadm: cannot delete IPMP interface ipmp0: IPMP group is not empty
root@unixrock:~#
root@unixrock:~# ipmpstat -g
GROUP       GROUPNAME   STATE     FDT       INTERFACES
ipmp0       ipmp0       ok        --        net1
root@unixrock:~# ipmpstat -i
INTERFACE   ACTIVE  GROUP       FLAGS     LINK      PROBE     STATE
net1        yes     ipmp0       --mbM--   up        disabled  ok
root@unixrock:~# ipadm delete-ip net1
root@unixrock:~# ipadm delete-ipmp ipmp0
root@unixrock:~# ipadm show-if
IFNAME     CLASS    STATE    ACTIVE OVER
lo0        loopback ok       yes    --
net0       ip       ok       yes    --
net3       ip       disabled no     --
net2       ip       disabled no     --
root@unixrock:~#
ERROR: ipadm: cannot create interface net2: Operation not supported on disabled object 
ERROR: ipadm: persistent operation not supported for enable-if
root@unixrock:~# ipadm create-ip net2
ipadm: cannot create interface net2: Operation not supported on disabled object
root@unixrock:~#
root@unixrock:~# ipadm show-if
IFNAME     CLASS    STATE    ACTIVE OVER
lo0        loopback ok       yes    --
net0       ip       ok       yes    --
net3       ip       disabled no     --
net2       ip       disabled no     --
root@unixrock:~# 
root@unixrock:~# ipadm enable-if net3
ipadm: persistent operation not supported for enable-if
root@unixrock:~# 
root@unixrock:~# ipadm enable-if -t net3
root@unixrock:~# ipadm enable-if -t net2
root@unixrock:~#
root@unixrock:~# ipadm show-if
IFNAME     CLASS    STATE    ACTIVE OVER
lo0        loopback ok       yes    --
net0       ip       ok       yes    --
net2       ip       down     no     --
net3       ip       down     no     --
root@unixrock:~#
Thanks for reading this post. Please leave your valuable comments and queries, I will get back to you at earliest possible.