root> show chassis cluter status
root> show chassis cluter interfaces
root> show chassis cluter statistics
root> show chassis cluter control-plane statistics
root> show chassis cluter data-plane statistics
root> show chassis cluter status redundancy-group 1

###Failover
node0 >  request system reboot

###Failback
node1 >  request system reboot

root> show chassis hardware detail
root> show version
root> show system license

• Control Link
• Fabric Link

root# delete
This will delete the entire configuration
Dlete everything under this level? [yes, no] (no) yes

root# set system root-authentication plain-text-password
root# commit

root> set chassis cluster cluster-id 1 node 0 reboot

root> set chassis cluster cluster-id 1 node 1 reboot

{primary:node0}
root> configure

root# set groups node0 system host-name srx1
root# set groups node0 interfaces fxp0 unit 0 family inet address 172.20.1.1/24

root# set groups node1 system host-name srx2
root# set groups node1 interfaces fxp0 unit 0 family inet address 172.20.1.2/24

root# set apply groups "${node}"

root# set interfaces fab0 fabric-options member-interfaces ge-0/0/0
root# set interfaces fab1 fabric-options member-interfaces ge-1/0/0

redundancy-group 0 is for routing engine redandancy.
redundancy-group 1 is for interface redandancy.

root# set chassis cluster redundancy-group 0 node 0 priority 100
root# set chassis cluster redundancy-group 0 node 1 priority 1

root# set chassis cluster redundancy-group 1 node 0 priority 100
root# set chassis cluster redundancy-group 1 node 1 priority 1

root# set chassis cluster redundancy-group 1 interface-monitor ge-0/0/3 weight 255
root# set chassis cluster redundancy-group 1 interface-monitor ge-0/0/4 weight 255

root# set chassis cluster redundancy-group 1 interface-monitor ge-1/0/3 weight 255
root# set chassis cluster redundancy-group 1 interface-monitor ge-1/0/4 weight 255

Reth is Redundant Ethernet Interface.

root# set chassis cluster reth-count 2

root# set chassis reh0 redundant-ether-options redundancy-group 1
root# set chassis reh0 unit 0 family inet address 10.10.10.200/24

root# set chassis reh1 redundant-ether-options redundancy-group 1
root# set chassis reh1 unit 0 family inet address 192.168.1.1/24

root# set interfaces ge-0/0/3 gigether-options redundant-parent reth0
root# set interfaces ge-1/0/3 gigether-options redundant-parent reth0

root# set interfaces ge-0/0/4 gigether-options redundant-parent reth1
root# set interfaces ge-1/0/4 gigether-options redundant-parent reth1

root# set security zones security-zone Untrust interfaces reth0.0
root# set security zones security-zone Trust interfaces reth1.0

root# commit check
root# commit

set chassis cluster disable reboot

Power the Juniper replacement on and check its version:

root@srx# show version

Note: both nodes must be running the same OS version.

I am going to assume both devices are on the same OS version.
Note: I'll write another How to later about how to upgrade the OS on an Juniper SRX.

root@srx# delete          ### Note: this command will delete the whole configuration and leave your device blank
root@srx# set system root-authentication plain-text-password
root@srx# commit

Once you have at hand your cluster ID and the node number, type in the following command:

root@srx> set chassis cluster cluster-id 1 node 0 reboot

Note: the command above will set your new Juniper to be part of cluster 1 and it will be node 0, then
it will reboot.

Returns all Configurations

root@srx> request system halt

Connect all the network cables “same as before”.

Power on the new device.

Check cluster status – both the nodes should be back online.

>show chassis cluster status

• Juniper SRX – replacement of a node in chassis cluster with IDP installed | iCookServers-&-Networks
• Replacing a Unit in a Cluster mode | SRX
• LivingUK - wonderful experiences in UK: How to replace a broken node in a Juniper SRX HA cluster