Detecting RTC SCM access not using Content Caching Proxy

One of our best practices for improved Rational Team Concert (RTC) Software Configuration Management (SCM) response times and reduced load on the RTC server is to use a content caching proxy server. These are located near users at servers in remote locations where the WAN performance is poor (high latency to RTC server). What is often missed, is that we also recommend they be placed near build servers, especially with significant continuous integration volume, to improve the repeated loading of source content for building.

This practice is not enforceable. That is, SCM and build client configurations must be manually setup to use the caching proxy. This is particularly troublesome for large remote user populations or where large numbers of build servers exist, especially when not centrally managed.

The question that naturally comes is how can one detect that a caching proxy is not being used when it should? One way is to look at active services and find service calls beginning with com.ibm.team.scm and com.ibm.team.filesystem for RTC SCM operations or com.ibm.team.build and com.ibm.rational.hudson for RTC build operations.

Since the IP address of the available caching proxies are static and known, you can find any entries on the Active Services page with a Service Name of any SCM or build related service calls that are not coming from an IP address (Scenario Id) belonging to a caching proxy. Since the active services entry captures the requesting user ID (Requested By), you can then check with the offending user to understand why the proxy wasn’t used and encourage them to correct their usage.

Active services detail is also available via the Active Services JMX MBean. If an an enterprise monitoring application is being used and integrated with our JMX MBeans, then it can be configured to capture this detail, parse it and generate appropriate alerts or lists to identify when a proxy is not being used.

One other option is to parse the access log for your reverse proxy.  Shown below is sample output from an IBM HTTP Server (IHS) access log.

The access log does not have user ID information but it does have the service calls and the IP address they are coming from.  You would need to have a way to determine associate an IP address with a user machine (for those entries not coming from a caching proxy).  Note that if a load balancer is used, the IP address recorded in the access log may not be the true IP address that originated the request.  For this reason and since the user ID information is not directly available, the Active Services method may be better.

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