Re: Multiple Load Balancers, stick table and url-embedded session support
Please see the thread: need help figuring out a sticking method I asked about this, Willie says there are issues figuring out a workable config syntax for 'regex to pull the URL/URI substring' but (I think) that coding the functionality is not technically super-difficult just not enough hands maybe and the config syntax? I have a feeling this would be a fairly commonly used feature, so it is good to see others asking the same question :) How are you planning to distribute the traffic to the different haproxy instances? LVS? Some hardware? On 12/8/10 8:58 PM, David wrote: Hi there, I have been asked to design an architecture for our load-balancing needs, and it looks like haproxy can do almost everything needed in a fairly straightfoward way. Two of the requirements are stickiness support (always send a request for a given session to the same backend) as well as multiple load balancers running at the same time to avoid single point of failure (hotbackup with only one haproxy running at a time is not considered acceptable). Using multiple HAproxy instances in parallel with stickiness support looks relatively easy if cookies are allowed (through e.g. cookie prefixing) since no information needs to be shared. Unfortunately, we also need to support session id embedded in URL (e.g. http://example.com/foo?sess=someid), and I was hoping that the new sticky table replication in 1.5 could help for that, but I am not sure it is the case. As far as I understand, I need to first define a table with string type, and then use the store-request to store the necessary information. I cannot see a way to get some information embedded in the URL using the existing query extraction methods. Am I missing something, or is it difficult to do this with haproxy ? regards, David
Re: Multiple Load Balancers, stick table and url-embedded session support
On Thu, Dec 9, 2010 at 7:27 PM, Hank A. Paulson h...@spamproof.nospammail.net wrote: Please see the thread: need help figuring out a sticking method I asked about this, Willie says there are issues figuring out a workable config syntax for 'regex to pull the URL/URI substring' but (I think) that coding the functionality is not technically super-difficult just not enough hands maybe and the config syntax? Actually if the key is to taken from a query param, that is relatively easy enough (I coded something myself for a client some time back based on 1.3.15.4). If, however, more flexibility is required (like in your case), then the point that Willie has mentioned will definitely come into play. -jf I have a feeling this would be a fairly commonly used feature, so it is good to see others asking the same question :) How are you planning to distribute the traffic to the different haproxy instances? LVS? Some hardware? On 12/8/10 8:58 PM, David wrote: Hi there, I have been asked to design an architecture for our load-balancing needs, and it looks like haproxy can do almost everything needed in a fairly straightfoward way. Two of the requirements are stickiness support (always send a request for a given session to the same backend) as well as multiple load balancers running at the same time to avoid single point of failure (hotbackup with only one haproxy running at a time is not considered acceptable). Using multiple HAproxy instances in parallel with stickiness support looks relatively easy if cookies are allowed (through e.g. cookie prefixing) since no information needs to be shared. Unfortunately, we also need to support session id embedded in URL (e.g. http://example.com/foo?sess=someid), and I was hoping that the new sticky table replication in 1.5 could help for that, but I am not sure it is the case. As far as I understand, I need to first define a table with string type, and then use the store-request to store the necessary information. I cannot see a way to get some information embedded in the URL using the existing query extraction methods. Am I missing something, or is it difficult to do this with haproxy ? regards, David
Re: Multiple Load Balancers, stick table and url-embedded session support
On 12/09/2010 08:27 PM, Hank A. Paulson wrote: Please see the thread: need help figuring out a sticking method I asked about this, Willie says there are issues figuring out a workable config syntax for 'regex to pull the URL/URI substring' but (I think) that coding the functionality is not technically super-difficult just not enough hands maybe and the config syntax? I have a feeling this would be a fairly commonly used feature, so it is good to see others asking the same question :) My use-case is pretty simple, since it was fullfilled without stick table using the appsession configuration parameter, e.g. appsession MYSESSIONID len 64 timeout 1h request-learn mode query-string IOW, I only need simple string matching, and that maybe be an acceptable first step ? How long do you think it would take ? I am relatively familiar with C, but have no knowledge of network programming nor I have ever looked into haproxy source code. How are you planning to distribute the traffic to the different haproxy instances? LVS? Some hardware? I don't know exactly - I think using somekind of DNS round robin scheme between our set of load balancers (we have something similar a the moment with pound as load balancer, but without any kind of sticky session support). We are required not to use hardware. cheers, David
Re: Multiple Load Balancers, stick table and url-embedded session support
Hi Jeffrey, On 12/09/2010 10:13 PM, Jeffrey 'jf' Lim wrote: On Thu, Dec 9, 2010 at 7:27 PM, Hank A. Paulson h...@spamproof.nospammail.net mailto:h...@spamproof.nospammail.net wrote: Please see the thread: need help figuring out a sticking method I asked about this, Willie says there are issues figuring out a workable config syntax for 'regex to pull the URL/URI substring' but (I think) that coding the functionality is not technically super-difficult just not enough hands maybe and the config syntax? Actually if the key is to taken from a query param, that is relatively easy enough (I coded something myself for a client some time back based on 1.3.15.4). Would that be something you could and would be willing to share ? regards, David
