[...]

sshagent (credentials: ['abn']) {

sh "env|grep SSH_AUTH_SOCK"

 script {
 def remote = [:]
 remote.name = 'abn'
 remote.user = 'user'
 remote.allowAnyHosts = true
remote.agent = true
remote.host = 'testserver'
 sshCommand remote: remote, command: "id"
 }

}

SSH_AUTH_SOCK=/tmp/ssh-0echbSIofhgV/agent.1971
com.jcraft.jsch.agentproxy.AgentProxyException: connector is not available: 
 at com.jcraft.jsch.agentproxy.ConnectorFactory.createConnector(ConnectorFactory.java:120)
 at com.jcraft.jsch.agentproxy.ConnectorFactory$createConnector.call(Unknown Source)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:117)
 at org.hidetake.groovy.ssh.connection.UserAuthentication$RemoteIdentityRepositoryLocator.get(UserAuthentication.groovy:53)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
 at org.codehaus.groovy.runtime.callsite.StaticMetaMethodSite$StaticMetaMethodSiteNoUnwrapNoCoerce.invoke(StaticMetaMethodSite.java:151)
 at org.codehaus.groovy.runtime.callsite.StaticMetaMethodSite.call(StaticMetaMethodSite.java:91)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:117)
 at org.hidetake.groovy.ssh.connection.UserAuthentication$Trait$Helper.configureUserAuthentication(UserAuthentication.groovy:28)
 at org.hidetake.groovy.ssh.connection.UserAuthentication$Trait$Helper$configureUserAuthentication$0.call(Unknown Source)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
 at org.hidetake.groovy.ssh.connection.ConnectionManager.configureUserAuthentication(ConnectionManager.groovy)
 at org.hidetake.groovy.ssh.connection.UserAuthentication$configureUserAuthentication$0.callCurrent(Unknown Source)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallCurrent(CallSiteArray.java:52)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:154)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:190)
 at org.hidetake.groovy.ssh.connection.ConnectionManager.connectInternal(ConnectionManager.groovy:104)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
 at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
 at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:384)
 at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1022)
 at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.callCurrent(PogoMetaClassSite.java:69)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallCurrent(CallSiteArray.java:52)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:154)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:190)
 at org.hidetake.groovy.ssh.connection.ConnectionManager$_connectInternal_closure1.doCall(ConnectionManager.groovy:85)
 at org.hidetake.groovy.ssh.connection.ConnectionManager$_connectInternal_closure1.doCall(ConnectionManager.groovy)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
 at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
 at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:294)
 at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1022)
 at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:42)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:117)
 at org.hidetake.groovy.ssh.util.Utility.retry(Utility.groovy:52)
 at org.hidetake.groovy.ssh.util.Utility$retry.callStatic(Unknown Source)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallStatic(CallSiteArray.java:56)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callStatic(AbstractCallSite.java:194)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callStatic(AbstractCallSite.java:222)
 at org.hidetake.groovy.ssh.connection.ConnectionManager.connectInternal(ConnectionManager.groovy:83)
 at org.hidetake.groovy.ssh.connection.ConnectionManager.connectInternal(ConnectionManager.groovy)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoCachedMethodSiteNoUnwrapNoCoerce.invoke(PogoMetaMethodSite.java:210)
 at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.callCurrent(PogoMetaMethodSite.java:59)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallCurrent(CallSiteArray.java:52)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:154)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:166)
 at org.hidetake.groovy.ssh.connection.ConnectionManager.connect(ConnectionManager.groovy:59)
 at org.hidetake.groovy.ssh.connection.ConnectionManager$connect.call(Unknown Source)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
 at org.hidetake.groovy.ssh.session.SessionTask.wetRun(SessionTask.groovy:61)
 at org.hidetake.groovy.ssh.session.SessionTask.call(SessionTask.groovy:48)
 at java_util_concurrent_Callable$call.call(Unknown Source)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:117)
 at org.hidetake.groovy.ssh.core.Service.run(Service.groovy:81)
 at org.hidetake.groovy.ssh.core.Service$run$0.call(Unknown Source)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
 at org.jenkinsci.plugins.sshsteps.SSHService.executeCommand(SSHService.groovy:170)
 at org.jenkinsci.plugins.sshsteps.steps.CommandStep$Execution$CommandCallable.execute(CommandStep.java:83)
 at org.jenkinsci.plugins.sshsteps.util.SSHMasterToSlaveCallable.call(SSHMasterToSlaveCallable.java:32)
 at hudson.remoting.LocalChannel.call(LocalChannel.java:45)
 at org.jenkinsci.plugins.sshsteps.steps.CommandStep$Execution.run(CommandStep.java:71)
 at org.jenkinsci.plugins.sshsteps.util.SSHStepExecution$1$1.call(SSHStepExecution.java:77)
 at hudson.security.ACL.impersonate(ACL.java:290)
 at org.jenkinsci.plugins.sshsteps.util.SSHStepExecution$1.run(SSHStepExecution.java:72)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
 at java.util.concurrent.FutureTask.run(FutureTask.java:266)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 at java.lang.Thread.run(Thread.java:748)