Apache HTrace is an Apache Incubator project providing an open source framework for distributed tracing. It can be used with both standalone applications and libraries.
HTrace was designed for use in big distributed systems such as the Apache Hadoop Distributed Filesystem and the Apache HBase storage engine. However, there is nothing Hadoop-specific about HTrace. It has no dependencies on Hadoop, and is a useful building block for many distributed systems. See the developer guide for information on adding HTrace support.
The API documentation for htrace-core is online.
Apache HTrace is an effort undergoing incubation at The Apache Software Foundation (ASF), sponsored by the Apache Incubator. Incubation is required of all newly accepted projects until a further review indicates that the infrastructure, communications, and decision making process have stabilized in a manner consistent with other successful ASF projects. While incubation status is not necessarily a reflection of the completeness or stability of the code, it does indicate that the project has yet to be fully endorsed by the ASF.