Alike Networking Requirements
Categories: Storage, Backup, System Requirements, XenServer, Hyper-V, Physical Systems, Alike v3
Get an overview of the networking requirements for Alike in this KB article.
*Please Note: The networking requirements for this article are relevant to Alike v3. Later versions of Alike may have different requirements.
For all XenServer communication Alike uses either http or https (TCP port 80 or 443). Although Alike only communicates with the pool master for all API calls, access to on all XenServer hosts in the pool may be necessary, since the Pool Master role is dynamic.
For all Hyper-V communication Alike uses WMI/DCOM.
For all communication with physical (Windows) servers, Alike uses WMI/DCOM, similar to Hyper-V.
Alike offers a unique backup method, known as Q-Hybrid. Q-Hybrid is a dynamic (“agentless”) agent based approach, which uses Windows VSS snapshots in order to protect the system. There is no installer or installation required on the guests; rather, Alike copies the tiny (~400KB) executables to the target system at the time of the job, and then cleans them out when finished.
This means there is zero administration of your backup targets, and all systems are automatically upgraded when you upgrade your Alike software. Q-Hybrid is available for all supported platforms (Xen, Hyper-V, and Physical), and networking requirements are the same for all.
Q-Hybrid requires remote WMI/DCOM access to the system being protected, from the Alike server. Alike must also be able to access the target system’s administrative CIFS share (admin$). Finally, the system being protected must be able to access the Alike DataStore (ADS) CIFS share, in order to store the backup data.
Enhanced Jobs are available for both XenServer and Hyper-V. For XenServer, Alike uses a small virtual appliance we call the ABD (Alike Backup Delegate). For Hyper-V, Alike does not require an ABD for any operations, and instead uses the host hypervisor for certain operations.
Enhanced jobs utilize the hypervisor’s native snapshot technology in order to protect the guest systems. In XenServer, these snapshots are taken, then transferred to the ABD appliance for processing, and deleted when complete. In Hyper-V, VHD(X) checkpoints/snapshots are used, and processing is performed on the hypervisor host.
The Alike Data Store (ADS)
The simplest of the three components is the ADS, which is a straightforward CIFS share that can reside on the Alike Server, or any CIFS compliant server or NAS device. Both the Alike services and the ABDs must be able to access the ADS on TCP 445 (CIFS).
If the ADS resides on the same server as the Alike services, the services will bypass CIFS automatcially, and access the DS directly.
The Alike Backup Delegate (ABD)
On Xenserver, all types of ‘Enhanced’ jobs (backup, restore and replication) require ABDs to function. ABDs are tiny ephemeral virtual appliances that Alike creates only for the duration of a particular job, cleaning them up afterwards.
During operation, each ABD will require 1 unique IP address. When no jobs are running, there will be no ABDs running in your pool.
- ABDs for Backup and Restore Jobs
For Enhanced Backup and Restore jobs, Alike will spawn a single ABD to perform its work. This ABD may be re-spawned many times throughout a job’s lifespan. During the job’s process, the Alike services must be able to access the ABD on their assigned or alternate IP address via TCP 22 for all control communications.
No significant bandwidth will be consumed over this connection. Instead, all data traffic will be routed directly to/from the ABD and the Alike DataStore on TCP 445.
- ABDs for Enhanced Replication Jobs
Enhanced replication jobs that require only 1 ABD have the exact same requirements as enhanced backup/restore jobs. However, for ER jobs that require 2 ABDs, there is an addition networking requirement for traffic between the ABDs themselves.
*Please Note: The networking requirements depend on the ‘data flow’ option selected in the ER job. For ‘push’ jobs (default), the source ABD must be able to access the destination ABD by either its ‘alternate IP’ or ‘assigned IP’ on TCP 22 and TCP 2812 (configurable).
Additionally, the source ABD must be able to access the Alike DataStore on TCP 445. N.B. The target ABD DOES NOT need to access the Alike DataStore.For ‘pull’ ER jobs, the flow and requirements are reversed. In pull jobs, the TARGET ABD must be able to access the SOURCE ABD on TCP 22 and TCP 2812 (configurable). Additionally only the TARGET ABD must be able to access the Alike DataStore on TCP 445.
- NAT IPs for ABDs
When assigning IP address for your ABDs, you have the option to provide a ‘NAT IP.’ If left blank, Alike will assign the given IP to the ABD, and all communication traffic to and from the ABD will use the assigned IP address.
However, to accommodate Natting and other networking needs, you may provide an ‘NAT IP’ for any ABD. When provided, Alike will assign the ‘assigned IP’ to the ABD vm, but all of Alike’s communications from the services and between ABDs in ER jobs, will use the ‘NAT IP.’
Alike Offsite vaulting requires 2 components:
- Your traditional ‘onsite’ Alike installation
- A remote ‘offsite’ module, which is installed on a seperate server.
The ‘onsite’ services of Alike initiate communication to the ‘offsite’ module and utilize a single TCP port: 2811 (default). The ‘offsite’ module may use NAT/PAT, and if so, the ‘onsite’ service must be configured to connect to the ‘offsite’ module’s public IP address.
- In order to perform leaf-coalesce jobs in XenServer 5.5, Alike requires TCP port 22 to be open for each XenServer in the job.
- Alike supports NAT/PAT for access of any of the XenServer Pool, or its offsite components, as long as the original port numbers are preserved.
- If you configure a Proxy Server for use in your environment, Alike will use the proxy settings instead of port 80 and 443.
- Alike will not use your proxy for any other required TCP port.