Newbie question

[tdunning]

I see in the other newbie question issue that cpud -d -init may be necessary when running outside of system startup. That helped me quite a bit to get a server started.

Once that server is started, I get a message cpuns not found which seems to imply that I need an executable called cpuns on either the server or the client side. It makes sense if cpu is trying to do namespacey things.

I don't, however, see anything with that name around.

Running cpu -ssh appears to work well which corroborates the idea that some sort of namespace executable or config is missing.

What is it that I don't know enough to ask?

Here is a transcript from the client side

tdunning@nodec:~/cpu$ cpu -key ~/.ssh/id_rsa  nodea
bash: line 25: cpuns: command not found
2025/04/03 01:31:25 SSH error Process exited with status 127
tdunning@nodec:~/cpu$ cpu -ssh -key ~/.ssh/id_rsa  nodea
2025/04/03 01:31:39 Running basic ssh protocol; no mounts
tdunning@nodea:~$ exit
tdunning@nodec:~/cpu$ 

And here are the outputs from the client and server sides with debug prints on

tdunning@nodec:~/cpu$ cpu -d -key ~/.ssh/id_rsa  nodea
2025/04/03 01:40:41 CPU:Running as client, to host "nodea", args ["/bin/bash"]
2025/04/03 01:40:41 CPU:getKeyFile for "/home/tdunning/.ssh/id_rsa"
2025/04/03 01:40:41 CPU:getKeyFile returns "/home/tdunning/.ssh/id_rsa"
2025/04/03 01:40:41 CPU:getPort("nodea", "")
2025/04/03 01:40:41 CPU:config.Get("nodea",""): "22"
2025/04/03 01:40:41 CPU:returns "22"
2025/04/03 01:40:41 CPU:turning ninep off for ssh usage
2025/04/03 01:40:41 CPU:turning srvnfs on for ssh usage
2025/04/03 01:40:41 CPU:connecting to "nodea" port "22"
2025/04/03 01:40:41 CPU:client:connect: err <nil>
2025/04/03 01:40:41 CPU:client:cpu:ssh.Dial(tcp, nodea:22, {{<nil> 0 [] [] []} tdunning [0x65d9c0] 0x665740 <nil>  [] 0s}): (&{0xc00020c500 {{{} 0} {0 0}} {{0 0} []} {0 0} map[]}, <nil>)
2025/04/03 01:40:41 CPU:client:Create New OSFS @ "/" with relative mount "."
2025/04/03 01:40:41 CPU:put . in 0
2025/04/03 01:40:41 CPU:client:ssh.listener 127.0.0.1:33261
2025/04/03 01:40:41 CPU:client:listener *ssh.tcpListener &{0xc000201bc0 0xc0000c4050 0xc0000ae2a0} addr 127.0.0.1:33261 port 33261
2025/04/03 01:40:41 CPU:client:uuid is "e3495ba4-bd29-4ce8-b533-4f6d532555a8"
2025/04/03 01:40:41 CPU:nfsmount "127.0.0.1:e3495ba4-bd29-4ce8-b533-4f6d532555a8 /tmp/cpu nfs rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,nolock,proto=tcp,port=33261,timeo=600,retrans=2,sec=sys,mountaddr=127.0.0.1,mountvers=3,mountport=33261,mountproto=tcp,local_lock=all,addr=127.0.0.1 0 0\n" fstab "\n/tmp/cpu/lib /lib none defaults,bind 0 0\n/tmp/cpu/lib64 /lib64 none defaults,bind 0 0\n/tmp/cpu/usr /usr none defaults,bind 0 0\n/tmp/cpu/bin /bin none defaults,bind 0 0\n/tmp/cpu/etc /etc none defaults,bind 0 0\n/tmp/cpu/home /home none defaults,bind 0 0\n" join "127.0.0.1:e3495ba4-bd29-4ce8-b533-4f6d532555a8 /tmp/cpu nfs rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,nolock,proto=tcp,port=33261,timeo=600,retrans=2,sec=sys,mountaddr=127.0.0.1,mountvers=3,mountport=33261,mountproto=tcp,local_lock=all,addr=127.0.0.1 0 0\n/tmp/cpu/lib /lib none defaults,bind 0 0\n/tmp/cpu/lib64 /lib64 none defaults,bind 0 0\n/tmp/cpu/usr /usr none defaults,bind 0 0\n/tmp/cpu/bin /bin none defaults,bind 0 0\n/tmp/cpu/etc /etc none defaults,bind 0 0\n/tmp/cpu/home /home none defaults,bind 0 0\n" env ["SHELL=/bin/bash" "PWD=/home/tdunning/cpu" "LOGNAME=tdunning" "XDG_SESSION_TYPE=tty" "MOTD_SHOWN=pam" "HOME=/home/tdunning" "LANG=en_US.UTF-8" "LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:" "SSH_CONNECTION=192.168.86.39 56532 192.168.86.14 22" "LESSCLOSE=/usr/bin/lesspipe %s %s" "XDG_SESSION_CLASS=user" "TERM=xterm-256color" "LESSOPEN=| /usr/bin/lesspipe %s" "USER=tdunning" "SHLVL=1" "XDG_SESSION_ID=912" "XDG_RUNTIME_DIR=/run/user/1000" "SSH_CLIENT=192.168.86.39 56532 22" "XDG_DATA_DIRS=/usr/local/share:/usr/share:/var/lib/snapd/desktop" "PATH=/home/tdunning/julia-1.6.2/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/tdunning/go/bin:/usr/local/go/bin" "DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus" "SSH_TTY=/dev/pts/0" "_=/home/tdunning/go/bin/cpu" "OLDPWD=/home/tdunning" "TMPDIR=/tmp" "CPU_FSTAB=\n/tmp/cpu/lib /lib none defaults,bind 0 0\n/tmp/cpu/lib64 /lib64 none defaults,bind 0 0\n/tmp/cpu/usr /usr none defaults,bind 0 0\n/tmp/cpu/bin /bin none defaults,bind 0 0\n/tmp/cpu/etc /etc none defaults,bind 0 0\n/tmp/cpu/home /home none defaults,bind 0 0\n" "LC_GLENDA_CPU_FSTAB=\n/tmp/cpu/lib /lib none defaults,bind 0 0\n/tmp/cpu/lib64 /lib64 none defaults,bind 0 0\n/tmp/cpu/usr /usr none defaults,bind 0 0\n/tmp/cpu/bin /bin none defaults,bind 0 0\n/tmp/cpu/etc /etc none defaults,bind 0 0\n/tmp/cpu/home /home none defaults,bind 0 0\n" "CPU_FSTAB=127.0.0.1:e3495ba4-bd29-4ce8-b533-4f6d532555a8 /tmp/cpu nfs rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,nolock,proto=tcp,port=33261,timeo=600,retrans=2,sec=sys,mountaddr=127.0.0.1,mountvers=3,mountport=33261,mountproto=tcp,local_lock=all,addr=127.0.0.1 0 0\n/tmp/cpu/lib /lib none defaults,bind 0 0\n/tmp/cpu/lib64 /lib64 none defaults,bind 0 0\n/tmp/cpu/usr /usr none defaults,bind 0 0\n/tmp/cpu/bin /bin none defaults,bind 0 0\n/tmp/cpu/etc /etc none defaults,bind 0 0\n/tmp/cpu/home /home none defaults,bind 0 0\n" "LC_GLENDA_CPU_FSTAB=127.0.0.1:e3495ba4-bd29-4ce8-b533-4f6d532555a8 /tmp/cpu nfs rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,nolock,proto=tcp,port=33261,timeo=600,retrans=2,sec=sys,mountaddr=127.0.0.1,mountvers=3,mountport=33261,mountproto=tcp,local_lock=all,addr=127.0.0.1 0 0\n/tmp/cpu/lib /lib none defaults,bind 0 0\n/tmp/cpu/lib64 /lib64 none defaults,bind 0 0\n/tmp/cpu/usr /usr none defaults,bind 0 0\n/tmp/cpu/bin /bin none defaults,bind 0 0\n/tmp/cpu/etc /etc none defaults,bind 0 0\n/tmp/cpu/home /home none defaults,bind 0 0\n"]
2025/04/03 01:40:41 CPU:start
2025/04/03 01:40:41 CPU:client:c.session.RequestPty("ansi", 51, 200, map[0x35:0x1 0x80:0x3840 0x81:0x3840]
2025/04/03 01:40:41 CPU:client:call session.Start( 'cpuns' '-env=SHELL=/bin/bash
PWD=/home/tdunning/cpu
LOGNAME=tdunning
XDG_SESSION_TYPE=tty
MOTD_SHOWN=pam
HOME=/home/tdunning
LANG=en_US.UTF-8
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:
SSH_CONNECTION=192.168.86.39 56532 192.168.86.14 22
LESSCLOSE=/usr/bin/lesspipe %s %s
XDG_SESSION_CLASS=user
TERM=xterm-256color
LESSOPEN=| /usr/bin/lesspipe %s
USER=tdunning
SHLVL=1
XDG_SESSION_ID=912
XDG_RUNTIME_DIR=/run/user/1000
SSH_CLIENT=192.168.86.39 56532 22
XDG_DATA_DIRS=/usr/local/share:/usr/share:/var/lib/snapd/desktop
PATH=/home/tdunning/julia-1.6.2/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/tdunning/go/bin:/usr/local/go/bin
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
SSH_TTY=/dev/pts/0
_=/home/tdunning/go/bin/cpu
OLDPWD=/home/tdunning
TMPDIR=/tmp
CPU_PWD=/home/tdunning/cpu' '/bin/bash')
2025/04/03 01:40:41 CPU:client:Setup interactive input
2025/04/03 01:40:41 CPU:wait
bash: line 25: cpuns: command not found
2025/04/03 01:40:41 CPU:close
2025/04/03 01:40:41 CPU:close done
2025/04/03 01:40:41 SSH error Process exited with status 127

 sudo PATH=$PATH /home/tdunning/cpu/bin/cpud -d -init
2025/04/03 01:39:10 CPUD:Args [/home/tdunning/cpu/bin/cpud -d -init] pid 373458 *runasinit true *remote false env [LANG=C.UTF-8 LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36: TERM=xterm-256color PATH=/home/tdunning/.local/bin:/home/tdunning/.juliaup/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/tdunning/cpu/bin MAIL=/var/mail/root LOGNAME=root USER=root HOME=/root SHELL=/bin/bash SUDO_COMMAND=/home/tdunning/cpu/bin/cpud -d -init SUDO_USER=tdunning SUDO_UID=1001 SUDO_GID=1001]
2025/04/03 01:39:10 CPUD:PID(373458):running as a server (a.k.a. starter of cpud's for sessions)
2025/04/03 01:39:10 CPUD:also running as init
2025/04/03 01:39:10 

  ####   #####   #    #   ##
 #    #  #    #  #    #   ##
 #       #    #  #    #   ##
 #       #####   #    #   ##
 #    #  #       #    #
  ####   #        ####    ##
2025/04/03 01:39:11 CPUD:Try to run [[/bin/sh] [/bbin/dhclient -v --retry 1000]]
2025/04/03 01:39:11 CPUD:Let's try to run [/bin/sh]
2025/04/03 01:39:11 CPUD:Run /bin/sh
2025/04/03 01:39:11 CPUD:Let's try to run [/bbin/dhclient -v --retry 1000]
2025/04/03 01:39:11 CPUD:it's not there
2025/04/03 01:39:11 CPUD:Kicked off startup jobs, now serve cpu sessions
2025/04/03 01:39:11 CPUD:server:configure SSH server
2025/04/03 01:39:11 CPUD:Server is &{:17010 0x1b85b0 [] linux arm64 <nil> <nil> 0x1b84b0 <nil> <nil> 0x1b86a0 0x1b87f0 <nil> <nil> <nil> 0s 0s map[] map[cancel-tcpip-forward:0x1b8910 tcpip-forward:0x1b8910] map[] {{} {{} {} 0} 0} {{{} {0 0}} 0 0 {{} 0} {{} 0}} map[] map[] {{} {{} {} 0} 0} <nil>}
2025/04/03 01:39:11 Listening on [::]:17010
# ls
Dockerfile  LICENSE  Makefile  README.md  TESTCPU  TESTDOCKERCPU  bin  client  cmds  configs  doc  ds  go.mod  go.sum  mount  p9cpu  server  session  sysvinit
# 

[rminnich]

First, welcome!

Second, you should not need to run cpud with -init unless you are really init. If I have a board with a shell prompt, meaning it ran init, I only run cpud or cpud -d.

cpud needs to be in $PATH, and a file named key.pub has to somewhere it will find it, or you can name it something else and use the -pk switch.

the cpu command (not cpud, cpu) checks to see if it is on port 22. If so, it will try to just run a cpuns command. If you have a working ssh on the target system, it's frequently easier to install cpuns in some standard place, so:
cd u-root/cpu/cmds/cpuns
CGO_ENABLED=0 GOARCH=arm5 go build . # or other arm stuff here
scp cpuns rpi:/usr/bin # or whatever your rpi is named

My test for whether to use cpud or cpuns: If I have to run the cpud by hand, by ssh'ing in to a system, cpuns makes more sense to use. If I want to build an initramfs from scratch, with u-root, then I'll use cpud. If I have something like a milk duo s, which uses sysv-like scripts, then install the script from the cpu repo, reboot, and you have cpud and sshd.

here's an example .ssh/config for milkv galaxy or whatever they call it:
host milkv
HostName 192.168.42.1
IdentityFile ~/.ssh/cpu_rsa
User root
Port 17010

here is for an ip6 host, running cpud
Host k10
User root
HostName fe80::fcfe:feff:fe1e:319b%enx00e04c6800ee
IdentityFile ~/.ssh/cpu_rsa
Port 17010

note that 17010 is known to IANA.

sorry the help is not clearer ...