So we are using Putty to connect to our server. Sometime when a user is running a job, they would have to wait for the job to be done before they can close the session. If they close the session before the job is done, it would corrupted. I wonder is there anyway we can stop the user from closing the session when something is running.
No, there is not. Tell your clients to use the screen command. This will create a separate session, then you run the long-running command (batch, ...). If you're disconnected, you just have to run screen -r to reconnect.
Related
Im writing a tool and one of its commands allows you to start a new session
How can I make a golang program restart itself? If your solution is OS-Strict im on Linux.
I tried
// exec from os/exec
exec.Command(os.Args[0]).Run()
but it doesnt work. I get a blank input session which is hard to explain
My Program Input: session new
:(
:(
each of the :( represent a blank line where im able to type stuff and hit enter, there are 2 which means i hit enter twice
Im expecting
My Program Input: session new
My Program Input:
Edit: more accurately, i want to make a subprocess of the same program
You could use a separate process, like radovskyb/gobeat.
Example:
sudo gobeat -pid=1234 -cmd="go run sendemail.go"
Run with sudo so gobeat will restart the server in the same terminal tty that it originated in. (sudo)
Point gobeat to the process of the running server that you want gobeat to monitor. (gobeat -pid=1234)
Set the cmd flag to run a Go file that will send an email notifying you that the server was restarted. (-cmd="go run sendemail.go")
If you do not want a separate process, then consider implementing a graceful upgrade
You can use the library cloudflare/tableflip for instance.
I have a bot machine (controlled via mobile device) which
connects to the Server and fetch information from it by method os
"ssh, shell script, os commands,sql queries etc" than it feed that
information over the internet (private)
I want to disallow this multiple connection to the server via the
bot machine ONLY.. there are other machine which connects to the server which must not be affected
Suppose
Client A from his mobile acess bot machine (via webpage) than the bot
machine connect to server (1st session) now if the process of this
connection is 5 minute during this period the bot machine will be
creating, quering, deleting, appending, updating etc
in the very mean time of that 5 minute duration (suppose 2min after
the 1st session started) Client B from his mobile access bot machine
(via webpage) than the bot machine connect to server (2nd session) now
it will conflict with the 1st session and create Havoc...
Limitation
Now first of all i do not want to editing any setting on the SERVER
ANY WHAT SO EVER
I do not want to edit the webpage/mobile etc
I already know abt the lock file method of parallel shell script and
it is implemented at script level but what abt the OS commands and
stuff like that which are not in bash script
My Thougth
What i thougt was whenever we create a connection with server it
create a process named what ever (SSH) which is viewable in ps -fu
OSUSER so by applying a unique id/tag/name to our connection we can
identify if one session is active or not. This will be check as soon
as the bot connects to the server. But i do not know how to do
that.... Please also suggest any more information over it.
Also is there is way to identify if the existing process is hanged or
the time of the process started or elapsed?
Maybe try using limits.conf to enforce a hard limit of 1 login for the user/group.
You might need a periodic cron job to check for and remove any stale logins.
Locks/mutexes are hard to get right and add complexity. Limits.conf is a standard feature of most unix/linux systems and should be more reliable, emphasis on should...
A similar question was raised here:
https://unix.stackexchange.com/questions/127077/number-of-ssh-connections-on-a-single-linux-machine
Details here:
http://linux.die.net/man/5/limits.conf
I assume you have a single login for the ssh account and that this runs a script on login
Add something like this to the script at login
#!/bin/bash
LOCK_FILE="/tmp/sshlock"
trap "rm $LOCK_FILE; exit" SIGHUP SIGINT SIGTERM
if [ $(( (`date +%s` - `stat -L --format %Y $LOCK_FILE`) < (30*60) )) ]; then
exit 0
fi
touch $LOCK_FILE
When the processes that the ssh login calls end, delete the $LOCK_FILE
The trap statement is an important part of this way of locking, please do use it
The "30*60" is a 30 minute timeout, thanks to the answer on this question How can I tell if a file is older than 30 minutes from /bin/sh?
I have many data-servers I need to download data from via http as soon as it is available. For each server I start a bash "while true"-loop and within that a wget to poll the server for new data. To start all the bashs I created a tmux config starting a window for every loop such loop and wget. This adds the benefit of easier inspecting what is happening.
I want to create a supervisor-service from this config, which would allow me to start, stop, and restart this tmux and its downloading clients all at once.
However, when I quit tmux, by the very nature of tmux, the bashs and their wgets keep running. Is there a way around that, so I can quit everything and restart everything with a simple supvervisorctl tmuxservice restart?
I'm trying to a background program that need to connect to window server, which is not allowed in a daemon. But may job is quite appropriate to be done in [System] session which daemons act.
I have tried to set session of the Agent.(Aqua by default)
LimitLoadToSessionType: System
But it didn't work.. Is it wrong? How can I do it?
May be [LoginWindow] + [Aqua] could match the right session. But between the two session, the program need to be shutdown and relaunched.
We're using a job scheduling system that runs on top of DBMS_JOB. It uses a master job to create one-time jobs. We deploy the same set of jobs to all our clients, but can specify which jobs should only run at certain clients.
We get occasional problems with a process run by a job hanging. The main cause of this is UTL_TCP not timing out when it does get an expected response. I want to be able to kill those jobs so that they can run again.
I'm looking at creating a new job that kill any of these one-time jobs that have been running for longer than a certain time.
We're stuck with Oracle 10g for a while yet, so I'm limited to what that can do.
There's an article that seems to cover most of this at
http://it.toolbox.com/blogs/database-solutions/killing-the-oracle-dbms_job-6498
I have a feeling that this is not going to cover all eventualities, including:
We run can jobs as several different users and a user can only break/remove jobs they created. I believe that I may be able to use DBMS_IJOB to get around that, but I need to get the DBA to let me execute it.
We have Oracle RAC systems. I understand 10g limits ALTER SYSTEM KILL SESSION to killing sessions on the current instance. I could arrange for all jobs to run on the same instance, but I've not tried that yet.
Anything else I should consider? Stack Overflow needs a definitive answer on this.
You can get the PID from the job tables and kill the stuck process via the normal OS commands.
You can kill jobs on any instance. On 10g, you need to know on which instance the stuck job is running, and connect to that instance:
To get your instance and pid:
select inst_id, process from gv$session where ...
Connect to a specific instance:
sqplus admin#node3 as sysdba
alter system kill session ...
There are more ways to kill a session on oracle. Depends on your plattform. Running on unix sessions (background jobs too) are represented by processes. Killing the process, kills the session. On windows sessions are represented by a thread. Killing the thread using orakill, kills the session. The process (or thread) id is stored in gv$process.