ERROR 2020-07-02 14:04:09:379 SkywalkingAgent-5-GRPCChannelManager-0 GRPCChannelManager : Create channel to apm-skywalking_oap:11800 fail.
java.lang.IllegalArgumentException: Invalid host or port: apm-skywalking_oap 11800
at org.apache.skywalking.apm.dependencies.io.grpc.internal.GrpcUtil.authorityFromHostAndPort(GrpcUtil.java:488)
at org.apache.skywalking.apm.dependencies.io.grpc.netty.NettyChannelBuilder.<init>(NettyChannelBuilder.java:133)
at org.apache.skywalking.apm.dependencies.io.grpc.netty.NettyChannelBuilder.forAddress(NettyChannelBuilder.java:119)
at org.apache.skywalking.apm.agent.core.remote.GRPCChannel.<init>(GRPCChannel.java:38)
at org.apache.skywalking.apm.agent.core.remote.GRPCChannel.<init>(GRPCChannel.java:29)
at org.apache.skywalking.apm.agent.core.remote.GRPCChannel$Builder.build(GRPCChannel.java:101)
at org.apache.skywalking.apm.agent.core.remote.GRPCChannelManager.run(GRPCChannelManager.java:115)
at org.apache.skywalking.apm.util.RunnableWithExceptionProtection.run(RunnableWithExceptionProtection.java:33)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
at java.base/java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305)
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.net.URISyntaxException: Illegal character in hostname at index 16: //apm-skywalking_oap:11800
at java.base/java.net.URI$Parser.fail(URI.java:2913)
at java.base/java.net.URI$Parser.parseHostname(URI.java:3448)
at java.base/java.net.URI$Parser.parseServer(URI.java:3297)
at java.base/java.net.URI$Parser.parseAuthority(URI.java:3216)
at java.base/java.net.URI$Parser.parseHierarchical(URI.java:3158)
at java.base/java.net.URI$Parser.parse(URI.java:3125)
at java.base/java.net.URI.<init>(URI.java:685)
at org.apache.skywalking.apm.dependencies.io.grpc.internal.GrpcUtil.authorityFromHostAndPort(GrpcUtil.java:486)
... 13 more
该问题是由于Skywalking agent连接到 oap-server，对于oap-server的主机名或者域名不能带有 _ 下划线，比较扯，docker swarm中生成的全名为 stack_servicename，对于swarm service直接使用servicename即可，总之skywalking不支持 _ 下划线的服务地址。需要避免该问题
