Daniel, Thanks. I'm reading the docs on sticky sessions. There is a lot of conflicting "how to's" out there but I'm making progress.
HB On Wed, Feb 28, 2018 at 12:21 PM, Daniel Ferradal <dferra...@apache.org> wrote: > > 3: Regarding my inquiry about potential better options, I was more > referring > > to the idea of maybe using Tomcat as a proxy to Tomcat backend > application. > > I've read it can be done was wondering if the like to like might provide > > advantages. I am personally not as familiar with Tomcat as I am with > HTTPD > > and therefore would prefer using HTTPD if there are no significant > reasons > > to use Tomcat --> Tomcat. > > IMO it is better to leave the application server to do what it is > supposed to do, handle dynamic content generation. While leaving > static content as well as balancing to httpd, which is what it does > best. > > > > > 4: The sticky sessions need makes sense. > > > > I have attempted to set up the sticky sessions configuration in HTTPD but > > unfortunately I must not have it set up properly. It's probably best if > I > > create a new thread for that issue and will do so. > > Sticky sessions can be very tricky to setup correctly. > > In mod_proxy_balancer docs it documents very well that you probably > need to set all these three elements correctly according to how tomcat > was setup: > > stickysession (the most obvious) > scolonpathdelim > route - according to the value jvmroute the tomcats have setup. > > > > > > > Thanks again for your guidance. > > > > HB > > > > On Fri, Feb 23, 2018 at 12:57 AM, Daniel Ferradal <dferra...@apache.org> > > wrote: > >> > >> Hello, > >> > >> I'll try to answer point by point the best I can. > >> > >> 1º You can only use one balancer method, so choose the best strategy > >> for your case. There is plenty on the description for each in the docs > >> (TL to explain here). > >> 2º No, it does not, you choose one and use only one that suites you > >> best for a specific balancer. > >> 3º Inside httpd the only non-third party choice that I know is > >> mod_proxy_balancer, so yes, by all means use it. Unless you find a > >> more suitable product for your needs. > >> 4º That will precisely mean you need to use sticky sessions and define > >> how to properly handle them at the balancer level, why? because as > >> long as nodes are up and running you want to deliver the session to > >> the specific node dealing with that session or session will be lost. > >> It is when that backend node is down that httpd should look for other > >> nodes to deliver the session. Afaik is called session persistence. Or > >> at least this is the usual way to balance with sessions dealt by a > >> backend cluster. > >> > >> About docs you can also visit: > >> http://httpd.apache.org/docs/2.4/howto/reverse_proxy.html > >> and mod_proxy itself: http://httpd.apache.org/docs/ > 2.4/mod/mod_proxy.html > >> > >> Cheers! > >> > >> 2018-02-23 1:48 GMT+01:00 Herb Burnswell <herbert.burnsw...@gmail.com>: > >> > All, > >> > > >> > I am looking for some guidance on using HTTPD as a proxy and load > >> > balancer > >> > to a backend Tomcat application. Specifically, I'm interested in how > to > >> > best handle the balancing of requests. The configuration would be > very > >> > much > >> > like the 'typical implementation' shown in this Reverse Proxy Guide: > >> > https://httpd.apache.org/docs/2.4/howto/reverse_proxy.html (I'm > using > >> > version 2.4.6): > >> > > >> > +--------------------- + > >> > | Firewall Public | > >> > +--------------------- + > >> > +-------------------------------------------+ > >> > | +------+ +-------+ +-------+ | > >> > | | httpd| | httpd | | httpd | | > >> > | | 1 | | 2 | | 3 | | > >> > | +------+ +-------+ +-------+ | > >> > +-------------------------------------------+ > >> > +---------------------- + > >> > | Firewall Private | > >> > +---------------------- + > >> > +---------------------------------------------+ > >> > | +--------+ +---------+ +--------+ | > >> > | | tomcat| |tomcat | |tomcat | | > >> > | | 1 | | 2 | | 3 | | > >> > | +--------+ +---------+ +--------+ | > >> > +---------------------------------------------+ > >> > > >> > > >> > We have this working fine with a vanity URL to a VIP on our public > >> > firewall > >> > --> to the 3 httpd proxy load balancer pool --> to one of the 3 > backend > >> > Tomcat server pool. We want everything to run over SSL and the > >> > currently > >> > working config on the httpd servers is basic: > >> > > >> > <VirtualHost _default_:443> > >> > > >> > ServerName example.com > >> > > >> > SSLEngine on > >> > SSLProtocol all -SSLv2 -SSLv3 > >> > SSLCipherSuite HIGH:MEDIUM:!aNULL:!MD5:!SEED:!IDEA > >> > > >> > SSLCertificateFile /etc/pki/tls/certs/ssl.crt > >> > > >> > # ------------------------------------------------ > >> > # Proxy Load Balancer > >> > # ------------------------------------------------ > >> > > >> > <Proxy balancer://mycluster> > >> > > >> > BalancerMember https://app1.example.com:9009 > >> > BalancerMember https://app2.example.com:9009 > >> > > >> > </Proxy> > >> > > >> > SSLProxyEngine on > >> > SSLProxyVerify none > >> > SSLProxyCheckPeerCN off > >> > SSLProxyCheckPeerName off > >> > SSLProxyCheckPeerExpire off > >> > > >> > ProxyPass / balancer://mycluster/ > >> > ProxyPassReverse / balancer://mycluster/ > >> > > >> > </VirtualHost> > >> > > >> > > >> > As mentioned, this works fine. But now we need to dig into the > request > >> > management. I read here: > >> > https://httpd.apache.org/docs/2.4/mod/mod_proxy_balancer.html that > the > >> > scheduler algorithm is provided by 'at least one of': > >> > > >> > mod_lbmethod_byrequests > >> > mod_lbmethod_bytraffic > >> > mod_lbmethod_bybusyness > >> > mod_lbmethod_heartbeat > >> > > >> > Questions: > >> > > >> > 1. Am I correct in reading 'at least one of' that multiple of these > >> > algorithms can be used together? If so, is there a hierarchy between > >> > them? > >> > > >> > 2. Does it make sense to use multiple algorithms? > >> > > >> > - It sounds like each could be desirable: > >> > mod_lbmethod_byrequests -> We do want to have an even distribution of > >> > request/sessions. > >> > > >> > mod_lbmethod_bytraffic -> Some requests/sessions could be more > intensive > >> > than others. > >> > > >> > mod_lbmethod_bybusyness -> Sounds similar to byrequests? > >> > > >> > mod_lbmethod_heartbeat -> Definately need to backend to be listening > but > >> > would be nice to distribute or overlook a server based upon response > >> > time. > >> > Is that part of how this works? > >> > > >> > 3. Is using HTTPD mod_proxy_balancer the best way to handle what we > are > >> > looking to do? Or are there better options? > >> > > >> > 4. On the backend we plan on using Tomcat session clustering for high > >> > availability. That being the case, would that mean that we would NOT > >> > want > >> > to use sticky sessions at the HTTPD level in case a backend Tomcat > node > >> > goes > >> > offline and the session is picked up on one of the other nodes? > >> > > >> > Sorry if I've confused anything here, any guidance is greatly > >> > appreciated. > >> > I'm happy to read any documentation directed to.. > >> > > >> > Thanks in advance, > >> > > >> > HB > >> > > >> > >> > >> > >> -- > >> Daniel Ferradal > >> HTTPD Docs. I translate to Spanish. > >> #httpd help at Freenode > >> > >> --------------------------------------------------------------------- > >> To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org > >> For additional commands, e-mail: users-h...@httpd.apache.org > >> > > > > > > -- > Daniel Ferradal > HTTPD is the best! > #httpd help at Freenode > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org > For additional commands, e-mail: users-h...@httpd.apache.org > >
