Cannot connect to mongodb replica set - mongodb

I'm using the datanucleus mongodb maven plugin and "access platform" for connecting my java app to mongodb using JPA.
I've followed the instructions on http://docs.mongodb.org/manual/tutorial/deploy-replica-set/
on a ubuntu VM, added db1.mongo, db2.mongo and db3.mongo into the hosts file on both the guest vm and the host (Mac OS X).
I got a simple java app connecting to the servers, (as described in http://www.datanucleus.org/products/accessplatform_3_0/mongodb/support.html).
When I connect the app to the primary (connection url: mongodb:db1.mongo:27017/ops?replicaSet=rs0) everything works just fine, but when I add the other two mongodb's to the connection url, so it becomes mongodb:db1.mongo:27017/ops?replicaSet=rs0,db2.mongo:27018,db3.mongo:27019 I get the exception:
com.mongodb.MongoException: can't find a master
at com.mongodb.DBTCPConnector.checkMaster(DBTCPConnector.java:503)
at com.mongodb.DBTCPConnector.innerCall(DBTCPConnector.java:236)
at com.mongodb.DBTCPConnector.call(DBTCPConnector.java:216)
...
I've searched for this error, but the ones I have found concerns use of localhost/127.0.0.1. I tried to mitigate that by running mongodb on a separate VM and thus a non-local IP as well as adding the names to the hosts file.
The primary goal with trying mongodb is to achieve availability so replication and being able to failover is extremely important. Transactions and consistency between nodes in case of failure is not a problem, neither are we concerned about loosing an update or two once in a while so mongodb looks like a good alternative using JPA (I'm utterly fed up with mysql :-)
Thanks in advance for your help!

I used multiple MongoDB servers when I originally wrote that support and worked back then. Not got time now, but you can look at the DataNucleus code that parses your datastore connection URL and converts it into MongoDB java API calls. Should strip the servers apart and then call "new Mongo(serverAddrs);". If its passing it in correctly (debugger?), then the problem is possibly Mongo-specific, as opposed to what DataNucleus does for you.
Also make sure you're using v3.1.2 (or later) of datanucleus-mongodb

I think you've misformatted your MongoDB URI. Instead of this:
mongodb:db1.mongo:27017/ops?replicaSet=rs0,db2.mongo:27018,db3.mongo:27019
Do this:
mongodb:db1.mongo:27017,db2.mongo:27018,db3.mongo:27019/ops?replicaSet=rs0

Related

running camunda with Spring boot & mongodb

Has anyone been able to get Camunda to run with Spring Boot and mongodb?
I tried several approaches and always got into a brick wall.
What I tried:
1. jpa / hibernate-ogm
I was able to initiate a connection to mongo after creating my own CamundaDatasourceConfiguration and ProcessEngineConfigurationImpl.
It failed when Camunda tried to get table metadata. I couldn't plug out this behavior.
2. jdbc driver for mongo by progress
I set up the jdbc url and driver class by progress.
Camunda then gets stuck during the startup process and does not get to the point where Jetty is fully started, i.e. the "Jetty started on port XYZ" message in the log.
3. camunda with postgres with mongo FDW
FDW is a mechanism for postress to interface an external datasource. This way an application can work with postgres over jdbc while the FDW will take care of reading and writing the date to the external source, be it a file, mongodb, etc.
After realizing 1 and 2 don't work, I started working on 3.
Has anyone succeeded in doing this and can share how?
so I ran into the same problem and decided to share my answers with you.
Currently it is not possible to run the Camunda-Engine with a NoSQL Database.
In this Camunda-Forum-Post one of the guys at Camunda also says it is not possible to run the engine completely without a database.
And in the offical Camunda-Docs there is also a list with all supported environments. Currently there are only SQL-Databases listed:
https://docs.camunda.org/manual/7.10/introduction/supported-environments/
But in some earlier Blog-Posts they metioned, that they want to make some proof-of-concept examples with the use of NoSQL-Databases. So we can expect, that these databases will be supported in the future, but not at the moment.
(note: the flowable engine is doing the same proof of concepts, they mentioned, that they want to be able to use NoSQL-databases by the end of the next year).

How can we access Bluemix hosted "Compose for MongoDB" service from "outside"?

Situation:
Have created today a new Compose for MongoDB Service instance in Bluemix
Need:
I have to access this MongoDB DIRECTLY with tools (eg. Mongo Managemant Studio Pro, mongo.exe, etc.) for bulkloading, testing, ad-hoc data fix, etc.
Problem:
I have not found any docs, samples nor a CLEAR statement that
a) gives me some confirmation that THIS is possible
b) gives me COMPLETE information (not just some technical fragments that might have worked year ago) how to do it.
Maybe I am looking to the wrong places or do not know the right people. However I am stuck on this, and before quitting Bluemix MongoDB maybe somebody has a copy/past solution or handson step by step manual.
Any help welcome. Thanks!
Connecting to MongoDB service in Bluemix from an application is possible. For this answer I have used the application "Robo3T" and here are the steps:
Access your MongoDB Service on you Bluemix account. Usually under
"Cloud Foundry Services"
Open section "Manage", from "Connection Settings" copy from "HTTPS" the connection address and port. In this example "sl-eu-lon-2-portal.5.dblayer.com" and "20651"
In Robo3T create a new connection with the connection address from previous step
In tab Authentication configure database name, username and password
. The credentials are found as in step 1
From "Connection Settings" copy the SSL Certificate into a text file and save locally.
In Robo3T Add the certificate to the connection in the "SSL" tab
Test the connection and save the settings
Answer
YES, Bluemix hosted Compose for MongoDB instances can be connected from the mongo Shell and some updated DB Managment tools.
However, you have to make sure, that in case you are running the newest DB versions, that your tools (shell and DB management GUIs) comply with the newest DB features such as encryption etc.
Origin of the Problem
My problem was due to older and therefore incompatible versions of the mongo shell and DB-managment tools running against the newest MongoDB versions with their specialities on encription and multiple servers to be handled in the URI.
At least two DB managment tools are not compatible with the newest DB version and will take their time to get fixed. The problem is, that both will not tell you about this. They just do not not connect. No logs on either side. Period.
So my advise here: look for tool providers who express dedicated compliance with the specific version of your DB.
Advise to the Bluemix Team
It might not take much time to provide some sample connection strings for the most common tools like the mongo shell, MongoBooster, etc. to take the hassle and guesswork out of interpreting the Environment variables and figuring out what is needed for specific connection strings and what is not.
For instance MongoDB Atlas hosting provides for every cluster readymade connection strings for many tools you can just copy/past and done!
Connecting to Atlas took me 5 Minutes. For Bluemix I have lost hours! Not because it is complex, but because the documentation and the generated Info is somehow incomplete and messy - at least for the ones who do not connection strings for their living!

Sitecore MongoDB not creating all database/collections

We are working on Sitecore deployment in Azure.
Sitecore Experience Platform 8.0 rev. 160115
MongoDB - 3.0.4
We installed MongoDB, and we can connect to localhost using Robomongo. We can only see “Analytics” database/collections.
Our connection strings setup are:
Connectionstring.config
But the other 3 databases and collections are not created.
Tracking.live
Tracking.history
Tracking.contact
In Sitecore.Analytics.config file – the setting “Analytics.Enabled” is set to true.
Sitecore.Analytics.config
In log we found some references to xDB cloud initialization failed issues, therefore we disabled it.
Are we missing any configurations? Any help or suggestions are appreciated.
Thank you
Keep in mind that MongoDB is schemaless. Of course, in a production environment you would probably have to create these databases manually - to ensure that access rights are assigned correctly. But in a development environment, any database can be created on the fly.
The only reason the analytics database was created for you is because Sitecore creates indexes for the Interactions collection. Otherwise, you wouldn't see this database until xDB wrote some data into it. Same goes for any MongoDB collection - those won't appear until there's either data being written or an index created.
The other three databases will be created once the aggregation/processing logic is executed. I.e. when your instance starts to actually collect and process visit data.
As a conclusion, don't worry about these databases missing (for now). Just verify that xDB functionality is working properly.

Not able to migrate the data from Parse to local machine

as some of you might aware about the shutting down of parse service in about a year, i am following the migration process as per their tutorials. However, i am not able to migrate these data from parse to local database(i.e. mongodb).
I've started the mongodb instanse locally on 27017, and also created an admin user as part of migration based on these tutorials. Reference-1 & Reference-2.
But when i try to migrate the data from parse developer console, i get No Reachable Servers or Network Error & i don't understand why. I have doubt in the Connection string that i use for this but i am not sure, please find the following image.
I am new to mongodb so don't have much idea about this, your little help would be greatly appreciated.
Since the migration tool runs at parse.com, the tool needs to be able to access your MongoDB instance over the Internet.
Since you're using a local IP (192.168.1.101), parse.com cannot connect to your IP and the transfer will time out.
Either you need to make your MongoDB reachable from the Internet, or you can - as they do in their guide - use an existing MongoDB service.

ReactiveMongo with Play 2 Framework saying "entire node set is unreachable"

I'm trying to get a Play (2.1) app with ReactiveMongo (0.9) working on the app's test server. However, when our application is run on my dev box, is able to store image metadata just fine, even pointing to the mongo 2.2 install on the mongo test server. Even ran it with "play stage", then run directly with java 1.6.0. However, run the same way, also with Java 1.6.0 on the test server, the app continuously logs this error:
r.c.a.MongoDBSystem - The entire node set is unreachable, is there a network problem?
r.c.a.MongoDBSystem - The entire node set is unreachable, is there a network problem?
r.c.a.MongoDBSystem - The entire node set is unreachable, is there a network problem?
And not just during initialization... it repeats indefinitely. I've seen this error mentioned elsewhere, but I don't think those solutions apply to this. From the app's test server, I'm able to telnet to port 27017 on the mongo test server successfully. I see both my local install and the test server install of the app log that it's using the same mongodb url.
So based on what I said, I believe I can eliminate:
Blocked port
Mongo server down
Pointing to wrong mongo server
Mongo version mismatch
Java version mismatch
I'm going through the reactivemongo source but it seems the error is spewed when the MongoChannels are not set as authenticating or ready state (usable). I'm planning to try remote-debugging to see where it's going wrong, but I'm running out of time on this, so I'm hoping for a troubleshooting tip or two if I can get any.
Thanks!
Alright, figured it out. We're running Casbah/Salat on the same app, for now. There's a mongodb.uri in the config file that gets read in by both. However, ReactiveMongo seems to only work if the database name is included, which according to the mongodb "connection string uri" spec:
http://docs.mongodb.org/manual/reference/connection-string/
... you only need to include the database if you have credentials you need to authenticate with. In our case, we don't have credentials, so Casbah wasn't including the database. I added it in anyway... casbah ignored it safely, and reactivemongo worked. I neglected to do the same in the test config file, so even though it was showing the correct host, it wasn't about to work correctly.
I see how the host url + db name in one string replaces the two fields "mongodb.servers" and "mongodb.db", but it can be confusing if not conforming to mongo's similar spec.