Forum Discussion
francisco_1_162
Nimbostratus
NimbostratusLoad balancing ltm virtual server
i have two datacenters with pair of ltm's. ltm's are connected to pair of gtm's load balancing the datacenters. the gtm's at each datacenter are connected to each other over the internet and also seeing the ltm's because they are loadbalcing the virtual servers on the ltm's.
The ltm's at each datacenters are running ltm licenses only. they can ping each other fine across the datcenters. my question is i would like to load balance a cirtix servers i have at each datacenters. citrix sever A 172.25.33.100 at datacenter A and cirtix server b at datacenter B 172.25.55.100. is it possible to create a single Virtual server between the ltm's (share the same virtual server) and have a pool with both servers on each ltms sharing the same VIP. the ltm's are on different subnet at each datacenter. or do i have two different VIP on the different subnet and create seperate pool on the ltm's and have the clients using two VIP's to connect to citrix servers instead of one!!. Please advise.
- No, you can't "share" a virtual server between 2 LTM configurations.
The recommended approach would be to create an LTM virtual server in each data center that sends traffic to a pool containing only the local citrix node with an appropriate health monitor applied.
Then add a WideIP to the GTM config that sends traffic to a pool containing those 2 virtual servers. (You may also want to configure persistence on the WideIP.)
HTH
/deb - (didn't quite finish my thought there, sorry...)
The WideIP is the DNS hostname by which you want your users to contact the citrix service. (It should be different from both of the real server DNS names.) When resolution of that name is requested, the GTM will hand out the address of one of the available servers. You can specify a number of load balancing methods to choose among them if more than one server is available.
/deb 
francisco_1_162thanks mate.
The cirtix servers i don’t want to be accessible from the internet, only internal users should access the citrix servers for now so do i still need to setup virtual server and wide IP on the gtm’s for the citrix servers for internal use only? The gtm’s interfaces are running on public ip address space. The gtm’s are seeing the ltm’s through natted ip’s on our firewalls. Please advice- francisco_1_162Hope i am making sense.
- JRahm
Admin
Configure GTM to hand out the real address for the vips instead of the translated address and you'll be fine. To summarize:
DC_A LTM:
VIP1
Pool members DC_A_Citrix, DC_B_Citrix
DC_B LTM:
VIP1
Pool members DC_B_Citrix, DC_A_Citrix
GTM
WideIP
Pool members DC_A VIP1, DC_B VIP1 (real addresses)
You might include some logic that if the DC_A vip is selected, the traffic will favor the DC_A citrix server, and similar for DC_B, to cut down on cross DC hops. - francisco_1_162good stuff. i will try it and let you guys know the outcome.
- francisco_1_162on the GTM's under WideIP, pool, i created a new pool. On the new pool properties, under members i cannot see the virtual servers i created on the ltm's. Infact the virtual servers are not appearing under data centers, servers. the reason why i believe is that the virtual servers i created on the ltm's are using private IP for the VIP so the GTM's will not discover this virtual servers automatically using virtual server discovery. do i need to created them manally on the GTM's before i can create a new WideIP pool? if so please provide instructions.
- JRahmGTM should discover them no matter what the IP's are if the servers are communicating effectively. Is your monitor for the server bigip? If not, it needs to be if discover is desired. Personally, I like to control everything, so I manually edit GTM. To verify iQuery, go to the command line of the GTM and run this command:
iqdump LTM IP Address
If you don't see traffic updating every 30s (default), or you get an error, then iquery is not working correctly.
If iQuery isn't working, you might need to exchange certs, install the GTM's version of big3d, or both.
bigip_add LTM IP Address
big3d_install LTM IP Address
To add VS manuall, go to Data Centers->Servers and click on your BigIP
Click the Virtual Server Tab, then click add
Here I would put in only the real IP in the address field, leave off the translation. Also, I don't use the monitor at the virtual server level since I get the status from iquery. - JRahmHmm, my gtm commands got truncated. I edited the previous post for clarity.
- francisco_1_162thanks.
