# Announcement regarding for replacement of kdesvr1 gateway server
#### tags: `admin`
The gateway server `kdesvr1.ccs.tsukuba.ac.jp` has been broken at Midnight on Tuesday, October 4th, 2022.
The server was replaced with the other server by leo and natsuki.

This new server can be accessed from outside of CCS but the other servers under this server cannot be connected to outside of the server cluster.（2022/10/14 reconnect network interface of gateway kdesvr1. 2022/10/18 Finally we could check the connection from internal CCS to outside of CCS.）

We can use computational resource in the server cluster, so please use them through the kdesvr1 using **sftp** or **rsync**, and so on.

We create the user accounts on the new gateway server.

# How to connect to the new gateway server
:::info
If you are using MS Windows OS(the Win OS), please use WSL or replace `~` with `C:\Users\UserName`. Moreover, if you are using older version than the version 1903 of Win OS, please substitute `ProxyCommand ssh -W %h:%p` with `ProxyCommand C:\Windows\System32\OpenSSH\ssh.exe -W %h:%p`.
:::

1. Reset known_hosts
- ssh-keygen -R kdesvr1.ccs.tsukuba.ac.jp
- ssh-keygen -R 130.158.108.54
- These commands will remove old kdesvr1's finger prints.
2. Update `~/.ssh/config`
- Please administrator of hpcsgitlab, which is the internal repository of KDE (Knowledge Data Engineering) lab
- If you are not willing to input pass phrase for private key everytime, we can use ssh-agent. Please search `ssh-agent`, too.
<!--
writed by [e-mail] Y=2022 M=10 D=18 JST=22:54
As pointed out by Hayase-sensei, "StrictHostKeyChecking no" setting has been removed because it causes a decrease in security. However, if the "Reset known_hosts" procedure is performed in advance, the connection can be established without problems.
-->

# Prevent from auto disconnection of ssh connection
ServerAliveInterval 60
# When you use ssh-agent, authorize using registered private key
ForwardAgent yes

Host kdesvr1
    User <user name>
# For student
    IdentityFile ~/.ssh/<private key inside the CCS KDE server cluster>
# For fuculties
    #IdentityFile ~/.ssh/<private key for svr05>
    HostName kdesvr1.ccs.tsukuba.ac.jp

Host hpcs*
    User <user name in the CCS KDE server cluster>
    Identity File ~/.ssh/<private key in the CCS KDE server cluster>
    ProxyCommand ssh -W %h:%p kdesvr1

Host hpcs115
    HostName 192.168.0.115

Host hpcs116
    HostName 192.168.0.116

Host hpcs117
    HostName 192.168.0.117
    Port 11722

Host hpcs119
    HostName 192.168.0.119

Host hpcs121
    HostName 192.168.0.121

Host hpcs122
    HostName 192.168.0.122

Host hpcs123
    HostName 192.168.0.123

# Only for user of internal GitLab server "hpcsgitlab"
Host hpcsgitlab
    User git
    IdentityFile ~/.ssh/id_rsa.hpcsgitlab
    ProxyCommand ssh -W %h:%p kdesvr1
    HostName 192.168.0.117

<!--
writed by [e-mail] Y=2022 M=10 D=18 JST=22:56
diff:
`chmod 700 -R ~/.ssh` -> `chmod -R 700 ~/.ssh`
I made the above change because MacOS behaves differently depending on the position of the options.
-->
3. Change permission of the files
- `chmod -R 700 ~/.ssh`
- `chmod 600 ~/.ssh/<private key name>`
4. Login to the kdesvr1
- `ssh kdesvr1`
- Please confirm the setting of identity file(path of private key). Password login is prohibitted in kdesvr1.
<!--
writed by [e-mail] Y=2022 M=10 D=18 JST=23:00
The current configuration is such that user impersonation is not possible. The password cannot be changed even if a user enters an empty password using the passwd command; it can only be overwritten by someone with root privileges by executing "sudo passwd ${username}".
5. **Important: set password for user account**
- `passwd`
- Input this command just after the first login to the kdesvr1
- If you are asked to change password for user, please set new password for user
- The password should be over 8 characters including large characters, small characters and numbers and symbol characters.
- If you do not change your password of user, any other registered user of kdesvr1 can use your account by next command
- `su <your user account name>`
-->
5. Check if you can login to the CCS KDE server cluster
- `ssh hpcsXXX`
- XXX is the ID number of the server you are using

# For administrator of CCS internal server
Please set gateway and DNS for network interface connection.
- gateway: 130.158.108.54
- dns: 130.158.108.3, 130.158.108.2

nmcli and nmtui is very useful.
At first please confirm the setting by nmtui. Please update gateway and dns information.

sudo nmtui

Next, please update gateway and dns setting by nmcli.

nmcli d # Network interface device and connection name list can be shown. 
ip addr show enp1s0f0(connection name) # Is IP address available? The subnetmask is 255.255.255.0, or ２４.
ip link show enp1s0f0 # Is it UP？ Otherwise, cable is disconnected to the connector. 
nmcli n # connected
nmcli n c # full
sudo nmcli con edit enp1s0f0(connection name)
print ipv4
remove ipv4.gateway
set ipv4.gateway 130.158.108.54
set ipv4.dns 130.158.108.3, 130.158.108.2
save
quit

After setting the network configuration, please restart NetworkManager.

sudo systemctl restart NetworkManager
sudo systemctl restart network # (or networking)
sudo systemctl restart systemd-networkd

If you wait a moment, you can connect to the outside of the CCS network from internal servers.
Thank you for reading.

EOF(End of File)