I sometimes can start the mongodb server and sometimes I cannot. What is the real problem with my mongodb server. I am using Mac and I am getting this problem for the first time.
I tried to kill the mongodb process but it didn't help me.
Any possible solutions would be highly appreciated.
The error I am getting is below.
For killing the process, I tried to kill 27017 and it says no process found.
I think you are confusing port and PID. When you kill 27017, you send the SIGKILL signal to a process whose PID is 27017. However, unless there is a coincidence, mongod does not need to have that PID. 27017 is the default port for mongod instances.
To kill it properly do the following:
ps -edf | grep mongod --> get the PID of the mongod process
Then:
kill -SIGKILL <pid>
Then start it again.
Related
Im learning mongoDB and exploring its features, i try several commands when i run the terminal and mongod acts like does not care. It always starts the server even though i simply run for reading help.
Some commands that i run
mongod --help
mongod --port 5000
mongod --dbpath C:\myfolder\myproj\data\db
Everytime, no matter witch i run from the above commands it starts the server always even when searching for help. The port and path do not change also, it looks like it ingores everything other than the mongod in the terminal. Any help?
mongod starts the service, but when you close the terminal then also the service terminates.
However, usually you install mongod as a Service. See mongod.exe for details.
Maybe this package will help you: mongoDB-oneClick
My mongodb run under Linux 6. I use the command db.shutdownServer() to close the database but the mongod process does not stop.
Stopping mongo directly with service mongod stop do a clean shutdown?
Thanks for your help
Proper ways to shutdown mongod is described in the documentation. They are:
Use shutdownServer()
From the mongo shell
use admin
db.shutdownServer()
Use --shutdown
From the Linux command line
mongod --shutdown
Use CTRL-C
When running the mongod instance in interactive mode, issue Control-C
Use kill
From the Linux command line
kill mongoProcessID
kill -2 mongodProcessID
So you need to figure out how /etc/init.d/mongodb stop actually stops the process on your Linux distribution. For example, on Debian it uses the wrapper which behaves similar to killall which is a proper method.
As per the documentation of mongodb, mongod --shutdown will work on linux system, but, on Mac, the --shutdown switch is not recognised. However, per the documentation, Ctrl+C will cleanly shutdown the db server. When you do a Ctrl+C on the same terminal where the db server is running, it initiates a dozen or so signalProcessingThread which indicates that the shutdown is proper and smooth. At the end, you can see that the process exits with code:0. Per the convention, Ctrl+C is awkward, but is clean, although not seemingly graceful.
Running MongoDB Shell v-3.2.8
I've noticed that articles and tutorials always mention to run the mongod server before running the mongo shell.
However, when I skip the first step and simply type mongo into my terminal, the mongo shell works without any errors / interruptions.
MacBook:Desktop user$ mongo
MongoDB shell version: 3.2.8
connecting to: test
Why does this work? Does mongo call mongod?
The mongod is being ran as a service or daemon, which means that there is always a mongod process running listening to a port. I use ubuntu, and when I install mongodb through the package manager, it immediately starts up a mongod process and begins listening on the standard port.
Running mongo is simply a small utility that attempts to connect to the localhost at the standard ip. The data reading, writing, and querying is done by the mongod process while mongo is a small program that sends the the commands to mongod.
If mongod wasn't running, you would see an error stating "Unable to connect to mongodb server"
I noticed the same. I think mongoose is doing some smart things there, which I'm not sure how it works. But I have noticed such things before, like mongoose will automatically add an "s" to your database's name when you declare it, which is a very thoughtful act =)).
I encountered the same thing and found that in the background services if MongoDB server is running, the mongo shell will work without any error. If we stop the service, the shell will throw an error.
Just finished installing mongodb, however, I have not been able to make complete sense of the difference between mongo vs mongod commands. Yes, I do understand that
mongod is the primary daemon process for the MongoDB system
and that
mongo is an interactive JavaScript shell interface to MongoDB
but what does that mean practically? I presume every time I want to use mongodb, I need to run mongod first. But then why am I able to run mongo without having started mongod first? Does mongo run mongod in the background automatically? Secondly, if I run mongod it eventually ends with something like
waiting for connections on port 27017
but then I can't type anything after that. Again, I presume that mongodb has been started in the background so I can safely close the terminal. But if I close the terminal by mistake (on a mac), how can I get that back up on the terminal? Also, how can I terminate the service for it to stop listening to the port?
So as you can I see, I have a bunch of simple questions... but most are related to the practical uses of when and when not to mongo or mongod. I can't seem to find anything online that will help me explain these in the practical sense.
As with most database software, Mongo is split into a server and client. The server is the main database component which stores and manages data. Clients come in various flavours and connect to the server to insert or query data.
mongod is the server portion. You start it, it runs, end of story.
mongo is a default command line client. You start it, you connect to a server, you enter commands, you quit it.
You have to run mongod first, otherwise you have no database to interact with. Simply running mongod on a command line will make it the frontmost running application, and it does not offer any interactivity. So yes, you'll just see something like "Waiting for connections...", and nothing more. You typically don't run mongod like that on the command line. You most typically create an init.d script or launchd file or however you manage your daemons, and have the system start it automatically at system boot time.
If you want to launch mongod as a one-off thing without having it permanently running on your systems, put it in the background:
$ mongod &
The & puts it in the background and you can continue to use your command line. You can see it and kill it like this:
~ deceze$ mongod &
[1] 1065
~ deceze$ jobs
[1]+ Running mongod &
~ deceze$ kill %1
[1]+ Done mongod
Once your server is running, start mongo, connect to the server, and interact with it. If you try to run mongo without a running server, it should complain that it's not able to connect:
~ deceze$ mongo
MongoDB shell version: 3.0.2
connecting to: test
2015-08-13T09:36:13.518+0200 W NETWORK Failed to connect to 127.0.0.1:27017, reason: errno:61 Connection refused
2015-08-13T09:36:13.521+0200 E QUERY Error: couldn't connect to server 127.0.0.1:27017 (127.0.0.1), connection attempt failed
at connect (src/mongo/shell/mongo.js:179:14)
at (connect):1:6 at src/mongo/shell/mongo.js:179
exception: connect failed
If your mongo shell does connect to something, you might unknowingly have another instance of mongod running on your system.
With mongodyou are starting the server on your machine. As you stated correctly, mongo is your client, your user interface, if you want to. Per default it connects to your local instance of MongoDB. If you start your client without a server instance running, you would have to 'tell' it, where it should connect to (e.g. a remote instance):
http://docs.mongodb.org/manual/reference/program/mongo/
Hello I'm testing mongo experimental version, which doesn't have an installer and is ran from directory by putting ./mongod but the problem is that the process quits whenever I close my ssh connection. What I'm supposed to do to keep it running even after closing ssh connection?
To start the mongod process as a background daemon you should run it with the parameters --fork (run as a daemon) and --logpath (a filename for log output).
You probably want to specify the --dbpath as well (unless you are OK with the default of /data/db).
So putting that together:
$ mongod --fork --dbpath /path/to/data --logpath /path/to/mongod.log
about to fork child process, waiting until server is ready for connections.
forked process: 64043
all output going to: /path/to/mongod.log
child process started successfully, parent exiting
$
After the server starts you will be returned to a command prompt.
If you want to shut down the server gracefully, log in via the mongo shell and run db.shutdownServer().
For more information see Manage mongod Processes in the MongoDB Manual.
It looks like that it is not started as a daemon so when you close your ssh session it got HUP signal. You can avoid it by using:
nohup command-to-start-mongo &