jupyterhub and Linux Data Science Virtual Machine on Azure. - azure

i try with success Linux Data Science Virtual Machine on Azure and jupyterhub. It's start automatically the first time, but when restart jupyter doesn't start anymore.
what I could try to solve the problem?
thank you!

JupyterHub automatically starts each time you start the VM, so it should be running after a restart. You can check the logs at a terminal with journalctl -u jupyterhub, and you can check the status of JupyterHub with systemctl status jupyterhub. You might try restarting the service with systemctl restart jupyterhub. It's also possible that you installed some software that broke the Jupyter kernel. See the notes here about a similar problem that someone else had.

Related

jupyterlab 500 error from dataproc cluster

i have been trying to open jupyterlab from my dataproc cluster. i had been working on it last week and there seemed to be some issue with the kernel. so i signed out of jupyterlab and stopped the cluster. then i tried to open jupyterlab again from the link under web interfaces in cluster detail. however, since last wednesday, everytime i try this i get a 500 or 502 error. the error says "500. That's an error. That's all we know."
i'm not sure what to do here. i googled the issue and couldn't find anything that would help.
You can SSH into the master node with gcloud compute ssh <cluster-name>-m, then check the status of the following 3 services:
systemctl status jupyter
systemctl status knox
systemctl status google-dataproc-component-gateway
Restart them if needed:
sudo systemctl restart jupyter
sudo systemctl restart knox
sudo systemctl restart google-dataproc-component-gateway
Also, check the Knox log at /var/log/knox/gateway.log.

PostgreSQL 9.5 doesn't start after reboot with systemd

I'm having a problem with PostgreSQL 9.5+173 on Ubuntu 16.04 and I happened to stumble across the following threads in my research that somewhat describes the behavior I'm seeing:
https://www.postgresql.org/message-id/CAFyxdeT%2B%3Dx-d0oNbFPoe%2B4xnt0Qdfi%2BzAEn%2BrQmEK0AZbJFRtg%40mail.gmail.com
https://www.postgresql.org/message-id/562E4453.5090803%40aklaver.com
Long story short I have a fresh install of Ubuntu 16 with nothing on it and PostgreSQL running. I've stopped PostgreSQL changed the data directory and port and a couple other settings and it starts back up fine.
I can start and stop PostgreSQL manually via systemctl without any problems. I can also connect to the database and can verify that it is running via a ps ax | grep postgres.
However, after I reboot PostgreSQL will not start up. Any attempt to start it up via systemctl start postgresql.service doesn't do anything and does not fail. The only way I am able to get it started is if I call systemctl start postgresql#9.5-main.service.
I did some investigation and looked at both the postgresql.service and postgresql#9.5-main.service scripts and realized that the postgresql.service script does nothing as stated in the thread above and that the postgresql#9.5-main.service has the PartOf directive which means it should be getting triggered from the postgresql.service as the sytemd docs state, but it isn't for some reason. Basically I'm at a loss as to why everything works before I reboot and then doesn't work after I reboot. Is there something I'm missing? I'm starting to go CRAZY over something so simple.
Update: I added an ExecStartPre=/bin/touch /tmp/postgresq.log to the postgresql#9.5-main.service to see if it's actually getting called on boot and it is not. Manually calling systemctl start postgresql#9.5-main.service creates the file in the /tmp directory.
Update: I have also found that calling systemd daemon-reload after reboot will allow me to start postgres via the systemctl start postgresql command.
Did you try doing systemctl enable postgresql? This will tell systemd to start this service after boot. Try rebooting after that.
Turns out that the problem was the fact that I symlinked /etc/postgresql/9.5/main/ across partitions to a custom partition that wasn't available right away, so when PostgreSQL tried to start on boot it couldn't because it's configuration files were not available. This describes what was happening since I could start PostgreSQL manually after I logged in.

No pid file for CouchDB on Ubuntu 14.04

We would like to monitor our CouchDB installation using the default pid file method with MONIT, however although couchdb is working fine there is no pid file generated under /var/run/couchdb, there is only a couch.uri file.
Permissions on /var/run/couchdb are good (couch:couch) and service couchdb stop and start work fine, although for MONIT to stop/start we would need the /etc/init.d/couchdb start/stop option (which again isn't present).
For info we just installed using apt-get install couchdb on Ubuntu 14.04.
Any advice appreciated.
Best regards
RichBos
I have done this with an older version (1.3) of CouchDB installed from source. Please check if this is working for you:
check process couchdb with pidfile
/usr/local/var/run/couchdb/couchdb.pid
group database
start program = "/etc/init.d/couchdb start -u couchdb"
stop program = "/etc/init.d/couchdb stop -u couchdb"
if failed host 127.0.0.1 port 5984 then restart
if cpu is greater than 40% for 2 cycles then alert
if cpu > 60% for 5 cycles then restart
if 10 restarts within 10 cycles then timeout
If you have installed it via a package manager, you will most likely find the pid in /var/run/couchdb/couchdb.pid
The place of the pid file did not change since 1.3. So chances are good, that it's working for you.

Cannot restart network service

I was trying to configure a static IP address on my Linux machine (Fedora 19 ). However when I was trying to restart my network.services using systemctl restart network.service, I was unable to do so.
[root#xyz network-scripts]# systemctl restart network.service
Job failed. See system journal and 'systemctl status' for details.
I tried to reboot my system and re execute the command, but still I am getting the same error. Also I am enable to access internet on my system.
Can anyone help me out with this.
To restart network services, you can use this command
service networking restart
You can also use
service networking stop
then
service networking start
restart the nm-applet with this command from terminal:
killall nm-applet; nohup nm-applet &
or restart the the network manager service using:
sudo systemctl restart network-manager
Restore radio frequencies by running the following command;
sudo service NetworkManager restart
If that does not work, run this one;
rfkill unblock wifi

Shutdown Cassandra server and then restart it in windows 7

I installed single node cluster in my local dev box which is running Windows 7 and it was working fine. Due to some reason, I need to restart my desktop and then after that whenever I am doing like this on the command prompt, it always gives me the below exception-
S:\Apache Cassandra\apache-cassandra-1.2.3\bin>cassandra -f
Starting Cassandra Server
Error: Exception thrown by the agent : java.rmi.server.ExportException: Port already in use: 7199; nested exception is:
java.net.BindException: Address already in use: JVM_Bind
Meaning port being used somewhere. I have made some changes in cassandra.yaml file so I need to shutdown the Cassandra server and then restart it again.
Can anybody help me with this?
Thanks for the help.
in windows7, with apache cassandra, a pid.txt file gets created at the root folder of cassandra. Give following instruction to stop the server:
d:/cassandra/bin> stop-server -p ../pid.txt -f
Running -f starts the server as a service, you can stop it through the task manager.
It sounds like your Cassandra server starts on it's own as a service in the background when your machine boots. You can configure windows startup services. To run cassandra in the foreground on windows simply use:
> cassandra.bat
If your are using Cassandra bundled with DataStax Community Edition and running as a service on startup of your machine then you can execute following commands to start and stop Cassandra server.
Start command prompt with admin rights
run following commands
net start DataStax_Cassandra_Community_Server
net stop DataStax_Cassandra_Community_Server

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