Re: IP change for a Linux guest
Note that the network management software differs by distro: RHEL uses NetworkManager (see Eric's answer below), SUSE uses wicked, and Ubuntu uses netplan - and beware: Some distros changed their tools over time: E.g. Ubuntu was formerly using NetworkManager at some point if I recall correctly. Each distro has a different user interface - so please consult your distro's manual, they usually have a good description of such tasks. Also, I'd recommend to setup a secondary interface and use that to perform the changes. With z/VM, it's really easy to setup a temporary IUCV connection between two guests (see small snippet below, needs to be performed on both sides - haven't tested it recently, but something along those lines). $ modprobe netiucv # Setup connection to guestB (peer) $ echo guestB>/sys/bus/iucv/drivers/netiucv/connection # Configure device $ ip addr add 192.168.2.1/16 dev iucv0 $ ip link set up dev iucv0 $ ip addr show iucv0 6: iucv0: mtu 9216 qdisc fq_codel state UNKNOWN group default qlen 50 link/slip inet 192.168.3.1/16 scope global iucv0 valid_lft forever preferred_lft forever Ciao, Stefan On 6/30/22 06:00, Eric Chevalier wrote: This is something I've done occasionally in our z/VM guests. All through an ssh session, no less! (Note that our Linux guests are running RHEL8.) In my case, I have a network connection called "enccw0.0.f804". I use the "nmtui" command to make any changes to the connection definition. Then I'll issue the command: nmcli conn down enccw0.0.f804 ; nmcli conn up enccw0.0.f804 The first nmcli command turns off the connection. The second nmcli brings the connection back up, picking up the changes I made with nmtui. Of course this will drop your connection to the original IP address, forcing you to re-establish an ssh connection to the new IP address. You have to stack the two nmcli commands as shown. Obviously, if you just use the first nmcli command you'll never be able to re-establish your ssh session. As a "back door": if I were to issue the first nmcli command without stacking the second, I could still get on to the Linux system by logging on to the guest using a 3270 session. Granted, Linux doesn't support 3270 sessions very well (at least not ours). Full screen applications like vim don't work very well on a 3270 session. But most command-line commands that read from stdin and write to stdout/stderr do work. So through my 3270 session I could issue the "nmcli conn up" command to re-enable ssh sessions. On 6/29/2022 10:15 PM, Peter wrote: Hello When an existing redhat Linux guest on zVM requires a IP change. What are files that I need to change to reflect with new IP address? For an existing Linux, how do I view it's console from a 3270 emulator ? Cause as of due to the IP change the Linux guest is not connectable via SSH. Could someone please guide me ? Regards Peter -- Eric Chevalier Phoenix Software International e...@phoenixsoftware.com Voice: (918) 491-6144 x410 Cell: (918) 629-6393 Fax: (918) 494-2701 This e-mail message, including any attachments, appended messages and the information contained therein, is for the sole use of the intended recipient(s). If you are not an intended recipient or have otherwise received this email message in error, any use, dissemination, distribution, review, storage or copying of this e-mail message and the information contained therein is strictly prohibited. If you are not an intended recipient, please contact the sender by reply e-mail and destroy all copies of this email message and do not otherwise utilize or retain this email message or any or all of the information contained therein. Although this email message and any attachments or appended messages are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by the sender for any loss or damage arising in any way from its opening or use. -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www2.marist.edu/htbin/wlvindex?LINUX-390 -- Mit freundlichen Grüßen / Kind regards Stefan Raspl Linux on Z --- IBM Deutschland Schoenaicher Str. 220 71032 Boeblingen Phone: +49-7031-16-2177 E-Mail: stefan.ra...@de.ibm.com --- IBM Deutschland Research & Development GmbH / Vorsitzender des Aufsichtsrats: Gregor Pillen Geschäftsführung: David
Re: IP change for a Linux guest
This is something I've done occasionally in our z/VM guests. All through an ssh session, no less! (Note that our Linux guests are running RHEL8.) In my case, I have a network connection called "enccw0.0.f804". I use the "nmtui" command to make any changes to the connection definition. Then I'll issue the command: nmcli conn down enccw0.0.f804 ; nmcli conn up enccw0.0.f804 The first nmcli command turns off the connection. The second nmcli brings the connection back up, picking up the changes I made with nmtui. Of course this will drop your connection to the original IP address, forcing you to re-establish an ssh connection to the new IP address. You have to stack the two nmcli commands as shown. Obviously, if you just use the first nmcli command you'll never be able to re-establish your ssh session. As a "back door": if I were to issue the first nmcli command without stacking the second, I could still get on to the Linux system by logging on to the guest using a 3270 session. Granted, Linux doesn't support 3270 sessions very well (at least not ours). Full screen applications like vim don't work very well on a 3270 session. But most command-line commands that read from stdin and write to stdout/stderr do work. So through my 3270 session I could issue the "nmcli conn up" command to re-enable ssh sessions. On 6/29/2022 10:15 PM, Peter wrote: Hello When an existing redhat Linux guest on zVM requires a IP change. What are files that I need to change to reflect with new IP address? For an existing Linux, how do I view it's console from a 3270 emulator ? Cause as of due to the IP change the Linux guest is not connectable via SSH. Could someone please guide me ? Regards Peter -- Eric Chevalier Phoenix Software International e...@phoenixsoftware.com Voice: (918) 491-6144 x410 Cell: (918) 629-6393 Fax: (918) 494-2701 This e-mail message, including any attachments, appended messages and the information contained therein, is for the sole use of the intended recipient(s). If you are not an intended recipient or have otherwise received this email message in error, any use, dissemination, distribution, review, storage or copying of this e-mail message and the information contained therein is strictly prohibited. If you are not an intended recipient, please contact the sender by reply e-mail and destroy all copies of this email message and do not otherwise utilize or retain this email message or any or all of the information contained therein. Although this email message and any attachments or appended messages are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by the sender for any loss or damage arising in any way from its opening or use. -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www2.marist.edu/htbin/wlvindex?LINUX-390
Re: IP change for a Linux guest
Peter, If you logon to the Linux guest via a 3270 display, you'll likely see a blank screen after logon (and password). Press Enter and you'll see VM READ in the lower right corner of the display. Press Enter again and you should see "Enter password" and RUNNING in the lower right corner of the screen. Give it some time until it tires of waiting for a password and asks for a userid. Enter a userid with sudo authority, or "root"; enter the password when prompted. Once you're logged in, you should be able to issue an "ip" command (or an "ifconfig" or whatever command works for you to dynamically enter a new IP address. Remember to update your default gateway with a "route add" command. You should then be able to ssh to the Linux guest. When you are done with the console interface, be sure the lower right corner of the display does NOT display CP READ, then enter the command "logout". Once you are prompted for a userid, enter the CP Break Key (key PA1 is the default), watch for CP READ in the lower right corner, then type "DISCONNECT" and press Enter. Your physical console (the 3270 terminal) will then be disconnected from the virtual console, and you can go about your business. Thanks, Sam (217) 862-9227 (office) (602) 327-2134 (cell) -Original Message- From: Linux on 390 Port On Behalf Of Peter Sent: Wednesday, June 29, 2022 20:16 To: LINUX-390@VM.MARIST.EDU Subject: IP change for a Linux guest Hello When an existing redhat Linux guest on zVM requires a IP change. What are files that I need to change to reflect with new IP address? For an existing Linux, how do I view it's console from a 3270 emulator ? Cause as of due to the IP change the Linux guest is not connectable via SSH. Could someone please guide me ? Regards Peter -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww2.marist.edu%2Fhtbin%2Fwlvindex%3FLINUX-390data=05%7C01%7CSam.Cohen%40LRS.COM%7C46dc80e5daa44e41f34908da5a472e55%7C62af9ccc42164ae2a1d306614c59c315%7C1%7C0%7C637921559055544780%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7Csdata=Os1EcNQi9oHXu3dRCdfcmNoUZDtwOKAPsS%2BNUTw6Ri8%3Dreserved=0 -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www2.marist.edu/htbin/wlvindex?LINUX-390
