I'm running Node.js and MongoDB on an Amazon EC2 instance.
Everything works perfectly if I run sudo mongod. I want to be able to close my ssh connection and have it still run, though, so I've been trying to get it going as a service.
I've changed the config so the db path is /data/db and done sudo chown -R mongodb:mongodb /data/db. Everything looks right permissions-wise when I do la -l.
When I try sudo service mongodb start, it says mongod start/running, process 4805, but that process is nowhere to be found in top (and, obviously, my app isn't hitting the db, or there would be no problem).
Trying without sudo, just service mongodb start, yields
start: Rejected send message, 1 matched rules; type="method_call", sender=":1.35" (uid=1000 pid=4809 comm="start mongod ") interface="com.ubuntu.Upstart0_6.Job" member="Start" error name="(unset)" requested_reply="0" destination="com.ubuntu.Upstart" (uid=0 pid=1 comm="/sbin/init ")`
I've tried mongod --repair as suggested in another question.
Everything else I'm seeing says it's a permissions issue, but the chown seems to have worked?
No idea what the Rejected send message is about.
Related
So, I was making an app that needs to use MongoDB transactions. But the Mongoose documentation told me that "MongoDB currently only supports transactions on replica sets, not standalone servers." So I thought I basically need to switch my Standalone MongoDB instance to Replica Set (whatever that means).
The MongoDB documentation gave me the instruction of how to do this with a few steps:
Shutdown the Standalone MongoDB instance
Restart the instance using the --replSet option
mongod --port 27017 --dbpath /var/lib/mongodb --replSet rs0 --bind_ip localhost
Connect the Mongo Shell
Call rs.initiate() inside the Shell
I'm stuck at step 2. All I know, when you want to start using MongoDB, you have to start its daemon first, using sudo systemctl start mongod, and then start using it by connecting your app. but that step told me to use mongod command to start the Mongod daemon, instead of systemctl. I tried the command but got the following error:
DBException in initAndListen, terminating","attr":{"error":"IllegalOperation: Attempted to create a lock file on a read-only directory: /var/lib/mongodb"}}
At first, I thought it was some kind of a privilege issue, so I ran it again with sudo but then it ended up destroying my entire database and prevented me from starting the MongoDB the "normal way" with giving me errors that I cannot remember.
I just reinstalled the whole MongoDB to get it back to work fine. Now I'm at the same place as yesterday, unable to convert to replica set, only now my entire database is gone. What do I do to enable it?
When running the mongod as a service, use /etc/monogd.conf to set the configuration. Note that the location or name of this file might have been changed in the mongod.service file in your system.
See replication options for how to set that in the file.
I am running mongod under Linux OS. I wanted to change my data directory from the default /var/lib/mongodb to another location say /nfs/mongodb.
When I run mongodb from shell(i.e. sudo /usr/bin/mongod --dbpath /nfs/mongodb) It works just fine.
Next step, I tried to run mongodb as a service(sudo service mongodb start)
I modified the file /etc/mongodb.conf and changed the line dppath=xxx to point to the new directory I created. When I run mongodb as service I get this error:
couldn't open file /nfs/mongodb/journal/j._0 for writing errno:1 Operation not permitted, terminating
Why the mongodb works in the shell and not as a service?
This is very likely because of permission issue.
When you run sudo mongod, it runs as root and can write to any directory.
In contrast, when running as a service, MongoDB typically runs as a limited-privilege user to prevent any security issue to escalate to root level access.
The solution is to chmod or chown the intended dbpath directory so that it's writeable by the service's user.
Note: you may want to check out the Production Notes for tips on running MongoDB optimally.
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.
I first try to connect via mongo, and I get the following:
Error: couldn't connect to server 127.0.0.1:<port> at src/mongo/shell/mongo.js:145
exception: connect failed
First, I've tried the following, as per answers here:
removed the sudo mongod.lock file with root permission
and tried sudo -u mongodb mongod -f /etc/mongodb.conf --repair
I received the error Can't specify both --journal and --repair options.
Then, I tried just using regular mongo --repair, and got the following:
file names: a list of files to run. files have to end in .js and will exit after unless --shell is specified
What is a way around these two erorrs, or what is the way to fix this? Thanks.
By restarting the server, the problem was solved:
service mongodb restart
And after this, it started as normal.
I'm getting the following error when I try to run "mongod" in the terminal. I've tried uninstalling, reinstalling, and restarting the machine. Any suggestions on how to get it working would be amazing.
ERROR:
dbpath (/data/db) does not exist.
Create this directory or give existing directory in --dbpath.
See http://dochub.mongodb.org/core/startingandstoppingmongo
Side note:
Node also stopped working on my machine around the same time that I got this error.
events.js:72
throw er; // Unhandled 'error' event
^
Error: failed to connect to [localhost:27017]
Any help would be much appreciated!
This should work to ensure that the directory is set up in the right place so that Mongo can find it:
sudo mkdir -p /data/db/
sudo chown `id -u` /data/db
You need to create the directory on root /data/db or set any other path with the following command :
mongod --dbpath /srv/mongodb/
See the example link
I solved the problem with :
sudo mongod --dbpath=/var/lib/mongodb and then mongo to access the mongodb Shell.
Change the user of the new data directory:
chown mongodb [rute_directory]
And try another time to start the mongo service
service mongod start
I solve the same problem with this.
Daemons (usually ending with d) are normally started as services. Starting the service (daemon) will allow mongodb to work as designed (without permission changes if integrates well with your distro). I start it using the service named mongodb instead of starting mongod directly--on distro with systemd enable on startup then run like:
sudo systemctl enable mongodb
sudo systemctl start mongodb
or, on distro with upstart (if you have /etc/init) or init (if you have /etc/init.d) ( https://www.tecmint.com/systemd-replaces-init-in-linux/ ) instead run:
sudo service mongodb enable
sudo service mongodb start
If you have a distro with rc ("run commands") such as Gentoo (settings in /etc/init.d) (https://forums.gentoo.org/viewtopic-t-854138-start-0.html) run:
rc-update add mongodb default
/etc/init.d/mongodb start
In a distro/version of FreeBSD which still has rc (check whether your version switched to systemd, otherwise see below):
add the following line to /etc/rc.conf:
mongod_enable="YES"
then:
sudo service mongod start
After starting the service, an unpriveleged user can use mongo, and each user will have separate data.
I also got the error that "The file /data/db doesn't exist" when I tried to save my file using the "mkdir -p /data/db" command(using both with and without sudo command). But later on one site, a person named Emil answered that the path "/data/db" no longer works on Mac, so use "~/data/db" instead
i.e., use the command
mkdir -p ~/data/db
instead of previous command.
Moreover, use
mongod --dbpath ~/data/db
to run mongod
It worked for me, hope it work for others too facing the same problem