I am not sure if this should be posted as an issue on the MongoDB github or should be posted here, so please bare with me.
What I want:
My first goal was to restart the monogd server using the Mongo Python API (pymongo). I guess that is theoretically impossible since after a shutdown, the API loses any link to the main server and can't ask it to restart.
So, I changed plans:
I just wanted to shutdown the server from my python code, pause the code (using input('Press enter')) allowing user to manually restart the mongod server and then press enter to continue the code execution after the user has restarted the server.
The way I "shutdown" the server from pymongo and wait for manual restart inside the code is as follows:
shell = MongoClient(uri)
shell['admin'].command('shutdown')
input("Press Enter button after restart.")
Problem is:
I keep getting an "AutoReconnect" error when doing this. Even after catching the error as follows:
try:
shell['admin'].command('shutdown')
except Exception as e:
if "closed" in str(e):
print("[UPDATE] Server was successfully shutdown. Please restart it.")
input("Press Enter button after you restart it.")
else:
raise e
Even after that, multiple "AutoReconnect" errors are raised. Without affecting the functionality of the code this time, just printing to stderr.
So, my question(s) are:
Is there a better way to restart the server from Pymongo? Possibly one that does not involve humnan intervention ?
How can I turn off the autoreconnect errors thrown ? Could not find any updated method to do so.
Related
I find that if I leave my VS Code Remote SSH connection open it disconnects automatically after a certain amount of time. Following automatic disconnection I find the Remote SSH then fails: when I try to log in again I get repeated requests for my remote password and every time I enter my password I just get another password prompt.
My current workaround is to go to the Command Palette and do "Remote-SSH: Kill VS Code Server on Host". Sometimes I need to do this multiple times for it to take effect. Then when I next log in there is a lengthy VS Code installation script that needs to run before I can start coding again.
Is there a way of setting up VS Code Remote SSH that avoids this issue? I have tried some of the suggestions on this page - https://code.visualstudio.com/docs/remote/troubleshooting. However I feel like I am completely in the dark regarding what the underlying issue is. I do not even know how I could go about generating informative diagnostics / a log.
Maybe the problem is that the remote machine has a limited number of proccess to run at same time. When a automatic disconnection of vscode happen, the that session is still running, but you cannot create a new one because you are over the limit in number of process.
In my case, asking to the remote machine to kill my process (manually done by the technician working in that machine in this case) works.
A better solution will be close the vscode sessions from your machine, to be able to start a new one again.
I've been using Mongo for a while now, and I never had any kind of errors. But today, I tried running the mongo command in my terminal and I got the following error:
Error connecting to 127.0.0.1:27017 :: caused by :: No connection could be made because the target machine actively refused it. :
I have my PATH variable for Mongo properly configured in my environment variables as follows:
C:\Program Files\MongoDB\Server\4.4\bin
so I doubt that is the issue. I remember going through my task manager yesterday and I accidentally terminated a program running in the background related to Mongo, but I can't seem to remember exactly what it was called, and I really think that that's the root of my problem, because before having terminated that Mongo program in my task manager I had never ran across this connection problem before.
By terminating a program in the background, I'm going to assume you didn't just end process, otherwise a simple computer restart would fix your issue. And in some cases, that same program would've relaunched when you launched MongoDB. But if you disabled a service and need to find which service needs to be running to be able to connect to your MongDB then I would suggest going through your Windows Services list and seeing which ones you disabled and looking one relating to TCP or SNMP.
This is because MongoDB Wire Protocol is a simple socket-based, request-response style protocol. You communicate with the database server through a regular TCP/IP socket and since you can't remember which one you "terminated" and any number of services related to networking can cause a dependency to be absent, I can't be more specific in helping you determine which one you need to turn back on and you'll have to do it through trial and error but I can at least offer you some guidance, hopefully.
Specifically you can either
Run system configuration using
msconfig
In a run box, navigating to the Services tab, order the list by Date Disabled to find the service that was disabled which correlates with when you when snooping through task manager, or
Run Task manager and navigate to the Services Tab, then Open Services, and order them by Status or by Name, and look for any service that includes TCP/IP, COM+, Port direction, etc. to see which one is disabled and change the configuration from anything but Disabled and then stat it manually and run MongDB again.
It's about as specific as I can get without knowing anything more than you terminated some program running in the background but I hope it helps.
The background process (daemon) for MongoDB is called 'mongod'. It's an executable in your bin directory inside your mongodb installation. You can just execute it in the terminal.
Run:
C:\Program Files\MongoDB\Server\4.4\bin\mongod.exe
I have a process in windows which i am running in startup. Now i need to make it if somehow that process get killed or stopped i need to restart it again in Windows 10?
Is there any way. Process is a HTTP server which if somehow stopped in windows i need to restart it. I have tried of writing a power-shell in which I'll check task-list status of process and then if not found I'll restart but that is not a good way. Please suggest some good way to do it.
I have a golang exe; under a particular scenario my process got killed or stopped i need to start it up again automatically. This has to be done imediately after the exe got killed. What is the best way to achieve this?
I will give you a brief rundown. You can enable Audit Process Termination in local group policy of the machine as shown below. In your case, success audits would be enough. Please note that the pic is for Windows 7. It may change with OS.
Now every time a process gets terminated, a success event will be generated and written to the security eventlog.
This will allow you to create a task scheduler that triggers on the generation of this event that calls a script that would run the process again. Simple right?
Well, you might have some trouble setting that task up especially when you want to pass details about the generating event to the script. This should help you get through that.
You can user Task scheduler for this purpose. There is a option of "restart on failure" which can be selected and whenever your process get failed it will restart again.
Reference :- https://social.technet.microsoft.com/Forums/windowsserver/en-US/4545361c-cc1f-4505-a0a1-c2dcc094109a/restarting-scheduled-task-that-has-failed?forum=winserverManagement
I have recently moved to a Mongo server that is running on a CentOS Google Cloud machine I've setup myself (the Mongo service started with systemct). Previously I've been running my mongo DB either locally, or via a server hosted by mlab.
Everything is working fine, except my client keeps getting StopIterator exceptions errors on any non-trivial query. I never encountered these previously, either running local or with the mlab server. Is there a timeout setting on the server I should be setting? (the client timeout settings don't seem to effect the issue)
So I have (sort of) answered my question. The reason my client app was dying was I was running from the Visual Studio debugger. That was catching the StopIterator and asserting, even though (I think) the StopIterator exception was being handled by the pymongo library which is re-trying and continuing successfully. If I disable that StopIterator exception in the "Python Exceptions" section of the VisualStudio "Exception Settings" panel, then my client code will continue and complete successfully.
That said, I am pretty sure this was not happening before I setup my own Mongo server (as well as the assert in VS there is an noticeable hitch when that exception occurs, both in my python code and in the mongo command line client). So I still believe there is something I am doing wrong with how I setup my Mongo server, so any suggestions on that would be welcome!
We're currently using chef to provision our servers and we want our recipe/cookbook to automatically add some data to the mongo database once its installed and running.
This is where we start to run into problems. We were using an execute resource to run the mongo script like this:
execute "install-mongodb-config" do
command "mongo #{node[:mongodb][:mongo_db_host]}/#{node[:mongodb][:mongo_db]} \"#{node[:mongodb][:mongo_add_config_script]}\""
action :run
end
This part of the recipe always failed no matter what we tried! I won't get into the details of everything we tried here (unless i need to) but lets just say that i've exhausted all possibilities of subscribes and notifies (i think).
The problem originates from the fact that we are using the mongodb::10gen_repo to install mongodb. The recipe exits when apt-get installs the package and then chef continues on to execute more resourses.
We have tried executing the above resource directly after mongodb::10gen_repo but it doesn't seem like mongodb is available and the mongo shell cannot connect and run the script. The error we see is somewhat like this:
MongoDB shell version: 2.0.2
Thu Sep 6 18:40:45 ReferenceError: setTimeout is not defined mongotest.js:2
failed to load: mongoAddConfig.js
Nothing we have tried has been able to get around this in a nice chef way. The thing that we resorted to was to replace the execute resource with the following:
execute "install-mongodb-config" do
command "sleep 60; mongo #{node[:mongodb][:mongo_db_host]}/#{node[:mongodb][:mongo_db]} \"#{node[:mongodb][:mongo_add_config_script]}\""
action :run
end
Which just makes the command sleep for 60 seconds before the mongo script is run. I know this isn't the Right way to do this but it works for now.
Can anyone suggest the Right way to do this? I have a feeling that I will need to talk to the guys that created the mongodb chef script and request a feature!
First of all. Remove this "sleep 60". This can be done by chef: All resources have common attributes and "retries" and "retry_delay" are part of them. So the easiest way would be:
execute "install-mongodb-config" do
command "mongo some_command"
action :run
retries 6
retry_delay 10
end
If you have more than 2-3 places, where you have to run some command on mongo database, consider creating LWRP, similar to one created in this mongodb cookbook. (Particularly check the libraries/mongodb.rb file). You can hide the logic that waits for the server to respond there.
Is it important that the same Chef run that installs the software also injects the initial configuration? The 'chefly' method to constructing cookbooks and recipes is to guard against idempotency in order to ensure that they can be run over and over again without producing unintended results.
In this particular case, I would limit the first recipe to only just installing and starting up mongodb. This recipe would do nothing if it saw that mongodb was already running on the host. Then, I'd have another recipe that would run only if it saw that mongo had been setup and was running. It would query the mongodb to see if the initial configuration had been done. If so, it would simply return. If not, it would run your configuration routine.
In this way, these recipes could run all the time, anytime, on your machine. Even if someone uninstalled mongodb, chef would get around to ensuring that it was set back up again and pristine.
So, I don't know much at all about chef. But your problem seems to be that you try to immediately connect after bringing the server up.
Server's are not immediately available when you bring them up since there is a bit of overhead that goes into electing a primary, getting all the server status's etc.
You can recreate this without chef by trying to bring up a replica set and immediately trying to connect to it in a simple script. So it's not chef specific.
Not sure if there is a way around the server startup lag since bringing up a primary is expected to be a relatively infrequent occurrence compared to just adding nodes to a set.
The only potential solution I see that is cleaner is adding a longer Timeout for the connection to be formed in the configuration. You can find how to do this in the mongodb documentation here: http://www.mongodb.org/display/DOCS/Connections
The flag of interest for you is likely connectTimeoutMS