This should have been done prior to installing the MDM/SDS backend. The plugin shouldn't let you continue until the SDC is installed.  Either way, go to your ScaleIO plugin on the vsphere web client. There will be a link for installing the SDC on the landing page there.  If you can't install it that way, you can do it manually. You downloaded it with the other ScaleIO software. Find the vib that is appropriate for your platform (5.5 or 6), copy it to your host and install it like any other vib on an ESXi host. Reboot the host after the initial install.
Fresh install with EMC ScaleIO v2.0-6035.0 using the vcenter plugin on VMware ESXi, 6.0.0, 3380124  During the deployment process, I get this error adding the slave MDM  FAILED (Error code: COMMUNICATION_ERROR) : Add Slave MDM  I already moved to a different set of esx servers (different hardware vendor) and got the exact same error.  I can ping between the hosts using the data IPs below.  Any ideas?  ------- Jul 19, 2016 8:17:00 PM Host: esx-a1-3.ilab.plexxi.com - SUCCEEDED: Install ScaleIO Module [IP: 172.25.200.3, module: TB] Jul 19, 2016 8:17:00 PM Host: esx-a1-2.ilab.plexxi.com - SUCCEEDED: Install ScaleIO Module [IP: 172.25.200.2, module: SLAVE_MDM] Jul 19, 2016 8:17:00 PM Host: esx-a1-1.ilab.plexxi.com - SUCCEEDED: Install ScaleIO Module [IP: 172.25.200.1, module: MASTER_MDM] Jul 19, 2016 8:17:00 PM Host: esx-a1-1.ilab.plexxi.com - STARTED: Add Master MDM [Mgmt IPs: [172.25.200.1], data IPs: [10.1.100.1, 10.1.101.1]] Jul 19, 2016 8:17:08 PM Host: esx-a1-1.ilab.plexxi.com - SUCCEEDED: Add Master MDM [Mgmt IPs: [172.25.200.1], data IPs: [10.1.100.1, 10.1.101.1]] Jul 19, 2016 8:17:08 PM Host: esx-a1-2.ilab.plexxi.com - STARTED: Add Slave MDM [Mgmt IP: 172.25.200.2, data IP 1: 10.1.100.2, data IP 2: 10.1.101.2] Jul 19, 2016 8:17:11 PM Host: esx-a1-2.ilab.plexxi.com - FAILED (Error code: COMMUNICATION_ERROR) : Add Slave MDM [Mgmt IP: 172.25.200.2, data IP 1: 10.1.100.2, data IP 2: 10.1.101.2] Jul 19, 2016 8:23:48 PM Host: esx-a1-2.ilab.plexxi.com - STARTED: Add Slave MDM [Mgmt IP: 172.25.200.2, data IP 1: 10.1.100.2, data IP 2: 10.1.101.2] Jul 19, 2016 8:23:52 PM Host: esx-a1-2.ilab.plexxi.com - FAILED (Error code: COMMUNICATION_ERROR) : Add Slave MDM [Mgmt IP: 172.25.200.2, data IP 1: 10.1.100.2, data IP 2: 10.1.101.2] Jul 19, 2016 8:37:48 PM Host: esx-a1-2.ilab.plexxi.com - STARTED: Add Slave MDM [Mgmt IP: 172.25.200.2, data IP 1: 10.1.100.2, data IP 2: 10.1.101.2] ------
Communication error adding Slave MDM