#create Unit
systemctl edit --full --force vmstatd.service

#systemd-nspawn
systemd-nspawn -D /var/lib/machine/rocky7 -b

machinectl str+altGr+9 

/var/lib/machines/rocky7

[Unit]
Description=vmstat as daemon

[Service]
Type=simple
ExecStart=/usr/bin/vmstat $VMSTAT_OPTS 3
EnvironmentFile=-/etc/default/vmstatd
StandardOutput=append:/var/log/vmstat.log

/etc/default/vmstatd
VMSTAT_OPTS=-ntw
VMSTAT_DELAY=3
VMSTAT_LOG=/var/log/vmstat.log

###############################
#oneShort beispiel
#vorbereitung 
cp -a /usr/share/doc /usr/share/doc2
#Unit
systemctl edit --full --force my_oneshot
[Unit]
Description=tar/untar doc2

[Service]
Type=oneshot
ExecStart=/usr/bin/tar -czf /usr/share/doc2.tgz /usr/share/doc2
ExecStart=/usr/bin/rm -r /usr/share/doc2

ExecStop=/usr/bin/tar -xvzf /usr/share/doc2.tgz
ExecStop=/bin/rm /usr/share/doc2.tgz
RemainAfterExit=yes

####################
#typen
#
#simple
#oneshot
#always
#
#
#Ubunut optimieren 
#rm /etc/iniramfs-tools/conf.d/resume
#update-initramfs -k all -u
#
#
systemd-cgtop besser als top

###############Unit mit Multiparameter
#
#Vorbereitung 
/etc/default/vmstatd
VMOPTS=-ntw
VMLOG=/var/tmp/vmstatd.log
VMDELAY=10
#VMCOUNT=
# Unit
[Unit]
Description=VMStat Daemon
StartLimitIntervalSec=2 min
StartLimitBurst=3
OnFailure=trig.service

[Service]
Restart=on-failure
RestartSec=20
RestartForceExitStatus=SIGHUP
EnvironmentFile=/etc/default/vmstatd
ExecStart=/bin/sh -c "exec /usr/bin/vmstat $VMOPTS $VMDELAY $VMCOUNT >> $VMLOG"
########################
#Namespace
# Beispiel mit ip
#Namespace erzeugen
ls -l /proc/self/ns
ip netns add ns1
ip netns exec ns1 /bin/bash
ip l
ip a
exit
ip netns pids ns1
ls -l /run/netns
ip netns del ns1

#veth (virtuelles Netzwerkkabel)
#Shell isolieren
ip link add name veth1 type veth peer name veth2
ip l
ip netns add ns1
ip link set dev veth2 netns ns1
ip l set dev veth1 up
ip addr change 172.16.0.1/16 dev veth1
ip netns exec ns1 ip l set dev veth2 up
ip netns exec ns1 ip addr change 172.16.0.2/16 dev veth2
ping 172.16.0.2
ip netns exec ns1 /bin/bash
ip a
ip r
ping 172.16.0.1
ip l del dev veth1
ip netns del ns1

#isolierter ssh-Server
#Zwei Fenster, z.B. in tmux, links=server, rechts=client

ip link add name vethsrv0 type veth peer name vethcli0
ip netns add srv
ip netns add cli
ip link set vethsrv0 netns srv
ip link set vethcli0 netns cli
ip l

#Server (links)
ip netns exec srv /bin/bash
ip link set up dev vethsrv0
ip addr change 10.9.8.7/24 dev vethsrv0 

#SSH Server starten
/sbin/sshd -dD

#Client (rechts)
ip netns exec cli /bin/bash
ip link set up dev vethcli0
ip addr change 10.9.8.6/24 dev vethcli0 

#Connect
ip a
ssh 10.9.8.7
ip a
exit
####################################