cat ยป /etc/ssh/ssh_config

Host *
        GSSAPIAuthentication yes
#       KexAlgorithms=diffie-hellman-group14-sha1
        KexAlgorithms=curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2- 
nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
      

cat > topology.yml

provider: libvirt
defaults:
  device: csr
nodes: [ r1, r2 ]
links: [ r1, r2, r1-r2 ]
hostname csr
no ip domain lookup
ip domain name lab.local
!
no service config
!
crypto key generate rsa modulus 2048
ip ssh version 2
!
aaa new-model
!
aaa authentication login default local
aaa authorization exec default local
!
username vagrant privilege 15 secret vagrant
!
ip ssh pubkey-chain
 username vagrant
  key-hash ssh-rsa DD3BB82E850406E9ABFFA80AC0046ED6
!
vrf definition MGMT
 description Management interface
 !
 address-family ipv4
 exit-address-family
!
interface GigabitEthernet1
 vrf forwarding MGMT
 description vagrant-management
 ip address dhcp
 no shutdown
!
line vty 0 4
 transport input ssh
!

event manager applet ENABLE-MGMT
 event syslog pattern "SYS-5-RESTART"
 action 0 cli command "enable"
 action 1 cli command "conf t"
 action 2 cli command "crypto key generate rsa modulus 2048"
 action 3 cli command "interface GigabitEthernet0/0"
 action 4 cli command "no shutdown"
 action 5 cli command "exit"
!
end
wr mem
!

https://netsim-tools.readthedocs.io/en/latest/labs/csr.html