Hi Tsz-Wo,
Thank you for your reply. I've been checking up on this a little bit
more and I believe the CNFE is my fault because I was trying to fix
another problem, which I'm going to try to explain:
Ratis-Metric is depending on the dependency
com.github.joshelser:dropwizard-metrics-hadoop-metrics2-reporter: 0.1.2.
This in turn depends on the org.apache.hadoop:hadoop-common:2.6.0. This
in turn depends on org.apache.hadoop:hadoop-annotations:2.6.0 which have
an dependency on a system scoped dependency named jdk.tools:1.6. I'm
running java 11 and this dependency doesn't exist in my environment so I
can't compile with ratis included in my project because it fails trying
to resolve that dependency.
However, the project ratis-hadoop depends on the the dependency
org.apache.hadoop:hadoop-common:3.1.1 (which should be upgraded to 3.1.2
because the sources are missing in 3.1.1) which doesn't have the
jdk.tools:1.6 dependency. So if I depend on this I can build the project
because the faulty 2.6.0 dependency is shadowed transitively by the
3.1.1 dependency and everything is compiling.
The simple fix would be updating so ratis-metric is depending directly
on the 3.1.2 dependency instead since it effectively will be the 3.1.1
code you are going run with anyway when running with the ratis-hadoop
dependency. I can open a bug for this.
I also have a question; right now there's a dependency on
io.dropwizard.metrics:metrics-core:3.2.5. It seems like there's an idea
that the metric loader functionality should/would be more pluggable
through the serviceloader API? Is this correct? I was merely thinking
that the ratis-metric project should be less opinionated on what library
one should use to measure things? I am willing to look into this if
needed and see if I can do anything about it.
I'm using dropwizard-metrics:4.0.5 which isn't compatible with the
current ratis-metrics implementation, and unfortunately I cannot
downgrade. I'd love to use ratis in my project, but this is something I
need to fix to be able to use it.
/Henrik
Den 2019-10-01 kl. 00:05, skrev Tsz Wo Sze:
Hi Henrik,
Thanks for reporting the problem.
org.apache.ratis.metrics.MetricsReporting imports
org.apache.hadoop.metrics2.lib.DefaultMetricsSystem, I guess it is
causing the ClassNotFoundException. It is a bug. Do you want to file
a JIRA?
Tsz-Wo
On Mon, Sep 30, 2019 at 2:23 AM Henrik Hegardt
<[email protected]> wrote:
Hi everyone,
I'm getting this error while running Ratis:
Caused by: java.io.IOException: java.lang.NoClassDefFoundError:
org/apache/hadoop/metrics2/lib/DefaultMetricsSystem
at org.apache.ratis.util.IOUtils.asIOException(IOUtils.java:54)
at org.apache.ratis.util.IOUtils.toIOException(IOUtils.java:61)
at org.apache.ratis.util.IOUtils.getFromFuture(IOUtils.java:70)
at
org.apache.ratis.server.impl.RaftServerProxy.getImpls(RaftServerProxy.java:284)
at
org.apache.ratis.server.impl.RaftServerProxy.start(RaftServerProxy.java:296)
at test.cluster.ClusterSevice.start(ClusterSevice.java:85)
... 65 more
Caused by: java.lang.NoClassDefFoundError:
org/apache/hadoop/metrics2/lib/DefaultMetricsSystem
at
org.apache.ratis.metrics.MetricsReporting.<clinit>(MetricsReporting.java:42)
at
org.apache.ratis.server.metrics.RatisMetrics.<clinit>(RatisMetrics.java:39)
at
org.apache.ratis.server.raftlog.segmented.SegmentedRaftLogWorker.<init>(SegmentedRaftLogWorker.java:176)
at
org.apache.ratis.server.raftlog.segmented.SegmentedRaftLog.<init>(SegmentedRaftLog.java:197)
at
org.apache.ratis.server.raftlog.segmented.SegmentedRaftLog.<init>(SegmentedRaftLog.java:183)
at
org.apache.ratis.server.impl.ServerState.initRaftLog(ServerState.java:188)
at
org.apache.ratis.server.impl.ServerState.<init>(ServerState.java:120)
at
org.apache.ratis.server.impl.RaftServerImpl.<init>(RaftServerImpl.java:110)
at
org.apache.ratis.server.impl.RaftServerProxy.lambda$newRaftServerImpl$2(RaftServerProxy.java:208)
at
java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1700)
at
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.ClassNotFoundException:
org.apache.hadoop.metrics2.lib.DefaultMetricsSystem
at
java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583)
at
java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
... 13 more
AFAICT this is a class in the dependency
org.apache.hadoop:hadoop-common:3.1.1. I'm running with the dependencies
and Ratis 0.4.0
<dependency>
<artifactId>ratis-server</artifactId>
<groupId>org.apache.ratis</groupId>
<exclusions>
<exclusion>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
</exclusion>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<artifactId>ratis-grpc</artifactId>
<groupId>org.apache.ratis</groupId>
</dependency>
And which should be enough according to the documentation. While it's
possible to include this dependency, it pulls in a lot of other
dependencies. While org.apache.ratis.metrics.MetricsReporting class does
have a dependency on the
org.apache.hadoop.metrics2.lib.DefaultMetricsSystem class, ratis-metrics
doesn't define a dependency to org.apache.hadoop:hadoop-common:3.1.1 in
its pom. Is this intended or am I missing something?
Thank you for all your efforts.
/Henrik
