Maven Wagon SCP is not able to establish a connection

I am trying to copy resources to another location. I am using maven wagon-ssh plugin to do this. It works fine locally, I am having issues when using Hudson/Jenkins.

My settings.xml file looks like this:

<servers>
    <server>
        <id>iq</id>
        <configuration>
            <knownHostsProvider implementation="org.apache.maven.wagon.providers.ssh.knownhost.NullKnownHostProvider">
                <hostKeyChecking>no</hostKeyChecking>
            </knownHostsProvider>
        </configuration>
        <username>user</username>
        <password>pass</password>
    </server>
</servers>

I tried this answer to skipping checking as I was getting:

Are you sure you want to continue connecting? (yes/no): The authenticity of host 'address' can't be established.
RSA key fingerprint is 10:.......:bb.

but now I am getting:

Could not apply configuration for iq to wagon org.apache.maven.wagon.providers.ssh.jsch.ScpWagon:ClassNotFoundException: Class name which was explicitly given in configuration using 'implementation' attribute: 'org.apache.maven.wagon.providers.ssh.knownhost.NullKnownHostProvider' cannot be loaded
org.codehaus.plexus.component.configurator.ComponentConfigurationException: ClassNotFoundException: Class name which was explicitly given in configuration using 'implementation' attribute: 'org.apache.maven.wagon.providers.ssh.knownhost.NullKnownHostProvider' cannot be loaded
    at org.codehaus.plexus.component.configurator.converters.AbstractConfigurationConverter.getClassForImplementationHint(AbstractConfigurationConverter.java:70)
    at .....

Caused by: java.lang.ClassNotFoundException: org.apache.maven.wagon.providers.ssh.knownhost.NullKnownHostProvider
    at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
    at org.codehaus.plexus.component.configurator.converters.AbstractConfigurationConverter.getClassForImplementationHint(AbstractConfigurationConverter.java:61)
    ... 37 more
The authenticity of host 'address' can't be established.
RSA key fingerprint is 10:.......:bb.
Are you sure you want to continue connecting? (yes/no): The authenticity of host 'address' can't be established.

Solution

maven apparently requires a ssh-rsa entry in the known_hosts file for the jenkins user. You can add the ssh-rsa entry to the file by issuing:

ssh-keyscan -t rsa YOUR_REMOTE_HOSTNAME >> ~jenkins/.ssh/known_hosts

[[ Added from another answer to make this one definitive. ]]

Instead, you might be able to add the following to the ~jenkins/.ssh/config. See: How to Avoid Maven builds stall on ssh host authenticity problem?

StrictHostKeyChecking no