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Martin Hope
toom
Asked: 2021-03-28 06:30:02 +0800 CST
  • 1

I have created the following systemd service to automatically keep an autossh tunnel open between two servers:

#Systemd unit file for autossh
[Unit]
Description=Autossh Tunnel

[Service]
Type=forking

ExecStart=/usr/bin/autossh -M 20009 -f -N -L 3307:127.0.0.1:3306 remoteServer
ExecStop=pkill autossh

User=ubuntu
Group=ubuntu
UMask=0007
RestartSec=1
Restart=always

[Install]
WantedBy=multi-user.target

The file is loacted in /etc/systemd/system/autossh-tunnel.service

When I run it I get the following error message:

ubuntu@verifier:~/.ssh$ sudo systemctl daemon-reload
ubuntu@verifier:~/.ssh$ sudo service autossh-tunnel start
Failed to start autossh-tunnel.service: Unit autossh-tunnel.service is not loaded properly: Exec format error.
See system logs and 'systemctl status autossh-tunnel.service' for details.
ubuntu@verifier:~/.ssh$ systemctl status autossh-tunnel.service
● autossh-tunnel.service - Autossh Tunnel
   Loaded: error (Reason: Exec format error)
   Active: inactive (dead)

which autossh yields:

ubuntu@verifier:~/.ssh$ which autossh
/usr/bin/autossh

I have also tried to run the exact same command /usr/bin/autossh -M 20009 -f -N -L 3307:127.0.0.1:3306 remoteServer in the console and I did not have any problems. However, as a systemd service it fails.

What is wrong here? I have another server with the same setup and there this script runs without any issues. So I do not understand what is going on here...

ssh ssh-tunnel systemd-service
Martin Hope
toom
Asked: 2019-01-30 20:06:53 +0800 CST
  • 1

I just installed a centos version on AWS. But I am not able to install openvpn.

When I try: sudo yum -y install openvpn I get this error message:

Geladene Plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.ratiokontakt.de
 * centosplus: mirror.fra10.de.leaseweb.net
 * extras: mirror.imt-systems.com
 * updates: mirror.fra10.de.leaseweb.net
Kein Paket openvpn verfügbar.
Fehler: Nichts zu tun

Sorry, this is in German (another thing that bothers me). But loosely translated it is like:

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
     * base: mirror.ratiokontakt.de
     * centosplus: mirror.fra10.de.leaseweb.net
     * extras: mirror.imt-systems.com
     * updates: mirror.fra10.de.leaseweb.net
No package openvpn available.
Error: Nothing to do

actually pretty weird. I do not understand why is does not find anything.

How do I solve this annoying problem?

centos
Martin Hope
toom
Asked: 2018-09-13 02:49:49 +0800 CST
  • 1

Please have a look at the following simple shell script startCleanup.sh:

#!/bin/sh
screen -d -m -S cleaner /usr/bin/python3 /opt/cleanup.py

My crontab looks like this:

* * * * * /opt/startCleanup.sh > /opt/cleanup.log 2>&1

When I run this script in the shell as a nomrally logged in user I do not have any problems. However, if I run this as a regular cronjob, no screen is started. Or better said: The screen is started (I think) but when the script finishes and along with the script the screen is also terminated.

Does anybody have an idea how to solve this problem?

thanks :)

UPDATE: Okay, I now defintely know that the screen is properly executed (I checked that by adding a sleep at the end of the bash script).

So here is what happens: The screen is created. BUT when the bash script finishes the screen is also terminated. So, the screen still depends on the script.

How can I avoid that the screen is terminated when the script finishes?

cron
Martin Hope
toom
Asked: 2014-01-31 15:07:57 +0800 CST
  • 1

I have two machines on Google compute engine and I want to ssh the other server. Therefore, on the first machine (namenode), I created a passwordless ssh key for user hadoop and did a cat id_rsa.pub >> authorized_keys. On the second machine (datanode1) there is also a user called hadoop. The second machine's hadoop user has an empty ~/.ssh directory.

When I now try to ssh from the first to the second machine I get:

hadoop@namenode:~/.ssh$ ssh -v hadoop@datanode1
OpenSSH_6.0p1 Debian-4, OpenSSL 1.0.1e 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to datanode1 [10.240.223.55] port 22.
debug1: Connection established.
debug1: identity file /home/hadoop/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /home/hadoop/.ssh/id_rsa-cert type -1
debug1: identity file /home/hadoop/.ssh/id_dsa type -1
debug1: identity file /home/hadoop/.ssh/id_dsa-cert type -1
debug1: identity file /home/hadoop/.ssh/id_ecdsa type -1
debug1: identity file /home/hadoop/.ssh/id_ecdsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.0p1 Debian-4
debug1: match: OpenSSH_6.0p1 Debian-4 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.0p1 Debian-4
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: sending SSH2_MSG_KEX_ECDH_INIT
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ECDSA 10:54:3e:ec:07:58:48:85:28:40:90:43:e1:8f:3d:f0
debug1: Host 'datanode1' is known and matches the ECDSA host key.
debug1: Found key in /home/hadoop/.ssh/known_hosts:1
debug1: ssh_ecdsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/hadoop/.ssh/id_rsa
debug1: Authentications that can continue: publickey
debug1: Trying private key: /home/hadoop/.ssh/id_dsa
debug1: Trying private key: /home/hadoop/.ssh/id_ecdsa
debug1: No more authentication methods to try.
Permission denied (publickey).

I do not understand what is happening here.

UPDATE: I did copy the id_rsa.pub to the authorized_keys file on the destination server. However, now I get the following error:

hadoop@namenode:~/.ssh$ ssh datanode1
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@       WARNING: POSSIBLE DNS SPOOFING DETECTED!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
The ECDSA host key for datanode1 has changed,
and the key for the corresponding IP address 10.240.226.88
is unknown. This could either mean that
DNS SPOOFING is happening or the IP address for the host
and its host key have changed at the same time.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
9f:8d:07:09:a9:67:63:b4:b9:2b:f5:39:ed:ef:55:d6.
Please contact your system administrator.
Add correct host key in /home/hadoop/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /home/hadoop/.ssh/known_hosts:1
ECDSA host key for datanode1 has changed and you have requested strict checking.
Host key verification failed.

Adding "StrictHostKeyChecking=no" to the /etc/ssh/ssh_config repaired this issue.

ssh
Martin Hope
toom
Asked: 2013-04-27 14:13:16 +0800 CST
  • 0

I want to start my tomcat server automatically on startup. Therefore I retrieved a simple LSB conform script from the net and modified it to my needs. This is the script:

# Provide logging functions like log_success_msg, log_failure_msg and log_warning_msg
. /lib/lsb/init-functions

[ -f /etc/default/rcS ] && . /etc/default/rcS
PATH=/opt/jdk1.7.0_21:/opt/apache-tomcat-7.0.39

case "$1" in
  start)
        /opt/apache-tomcat-7.0.39/bin/startup.sh
        ;;
  stop)
    /opt/apache-tomcat-7.0.39/bin/shutdown.sh
        ;;
  restart|force-reload)
        ;;
  status)
        ;;
  *)
        log_failure_msg "Usage: {start|stop|restart|force-reload|status}"
                exit 1
esac

exit 0

Now, I copied it to /etc/init.d and applied a "chmod +x tomcat" on it. Then I tried to run it 

/etc/init.d # ./tomcat start
/opt/apache-tomcat-7.0.39/bin/startup.sh: 1: /opt/apache-tomcat-7.0.39/bin/startup.sh: uname: not found
/opt/apache-tomcat-7.0.39/bin/startup.sh: 1: /opt/apache-tomcat-7.0.39/bin/startup.sh: dirname: not found
Cannot find /catalina.sh
The file is absent or does not have execute permission
This file is needed to run this program

What am I missing here?

tomcat
Martin Hope
toom
Asked: 2012-11-04 07:28:18 +0800 CST
  • 0

I want to encrypt the http traffic on a tomcat instance via ssl. Therefore I followed the most simplistic approach described on various webpages. But anyway it simply does not work. Here is what I did:

  1. "keytool -genkey -alias tomcat -keyalg RSA" and I enterd "changeit" as the password (since this is the defaut chosen by tomcat)

  2. Altering $CATALINA_HOME/conf/servers.xml by uncommenting the following line

    Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" clientAuth="false" sslProtocol="TLS"/

  3. Restarting tomcat

Entering 

https://localhost:8443

does not work. However, I can still access the page via normal http like 

http://localhost:8080

The logfile does not contain any suspicious information.

What is going wrong here?

ssl
Martin Hope
toom
Asked: 2012-03-13 13:19:17 +0800 CST
  • 3

I just got a virtual server (I think virtuozzo) with root access. I wanted to install shorewall but when I want to start it I get the error message

# shorewall start
Compiling...
Processing /etc/shorewall/shorewall.conf...
ERROR: Your kernel/iptables do not include state match support. No version of Shorewall will run on this system

So now I'm wondering what can I do? The system ist ubuntu 11.10.

firewall ubuntu virtuozzo