Adding an host with engine running on Fedora 28 server fails with: 2018-06-15 17:08:23,478+02 ERROR [org.ovirt.engine.core.uutils.ssh.OpenSSHUtils] (default task-2) [b9fdcbba-a577-4923-a718-c45f56aa0830] The key algorithm 'EC' is not supported, will return null. 2018-06-15 17:08:23,485+02 ERROR [org.ovirt.engine.core.bll.hostdeploy.AddVdsCommand] (default task-2) [b9fdcbba-a577-4923-a718-c45f56aa0830] Failed to establish session with host 'host': null Involved packages: ovirt-engine-4.3.0-0.0.master.20180613124113.git0abf28f2d59.fc28.noarch # rpm -qav |grep ssh|sort apache-sshd-0.14.0-7.fc28.noarch fence-agents-ilo-ssh-4.2.1-1.fc28.x86_64 libssh-0.7.5-7.fc28.x86_64 libssh2-1.8.0-7.fc28.x86_64 openssh-7.7p1-3.fc28.x86_64 openssh-clients-7.7p1-3.fc28.x86_64 openssh-server-7.7p1-3.fc28.x86_64 sshpass-1.06-5.fc28.x86_64 Not sure if related to bug #1441528
If it may help: rpm -qf /etc/crypto-policies/back-ends/openssh.config crypto-policies-20180425-5.git6ad4018.fc28.noarch cat /etc/crypto-policies/back-ends/openssh.config Ciphers aes256-gcm,chacha20-poly1305,aes256-ctr,aes256-cbc,aes128-gcm,aes128-ctr,aes128-cbc MACs hmac-sha2-256-etm,hmac-sha1-etm,umac-128-etm,hmac-sha2-512-etm,hmac-sha2-256,hmac-sha1,umac-128,hmac-sha2-512 GSSAPIKexAlgorithms gss-gex-sha1-,gss-group14-sha1- KexAlgorithms curve25519-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1
Also note workaround mentioned in https://www.ovirt.org/release/3.6.1/#fedora-22 is not working: " Fedora 22 on hosts you need to add following line to /etc/ssh/sshd_config KexAlgorithms curve25519-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 and then execute # systemctl restart sshd before adding the host to the engine. "
This issue could be related to this [1] jdk bug. [1] https://bugs.openjdk.java.net/browse/JDK-8182580
There is no progress on JDK-8182580 for year, but the issue seems to be working on JDK9, so we will most probably need to upgrade to JDK9/10 on Fedora to resolve the issue.
for knowledge preserving, the current workaround is to comment out the line: "HostKey /etc/ssh/ssh_host_ecdsa_key" from /etc/ssh/sshd_config on the host