Hadoop cluster java.net ConnectionException: Connection refused error - java

I used to have a hadoop cluster running with centos 6.5 that was built using a gui. It made everything work perfectly. For a bunch of reasons that are not relevant i needed to upgrade to centos 7. The gui i used to install it on 6.5 just doesnt have centos 7 as an option. As a result I have to manually install it on a new centos 7 cluster. I keep running into this error.
Call From Cluster-Client-1/ip.add.ress to Cluster-Client-1:8020 failed on
connection exception: java.net.ConnectException:
Connection refused; for more details see the website
The relevant port on my cluster is 50010 so i think where it says "cluster-client-1:8020 that it should say 50010 but i dont know where that appropriate file is or how to change it. The ip-address is correct. You probably need more information to answer my question. but I don't know what you need so please ask away. There are currently no slave nodes in the cluster I'm in the process of adding more but i need to solve this error before i can move on.
Please help

Related

Can't connect to remote MongoDB from Gradle, even if I can connect from command line

I have a remote MongoDB that I need to connect to. I have all the credentials, but when trying to connect from gradle with this.mongoClient = MongoClients.create(dbConnectionString);, I get following error:
java.io.UncheckedIOException: java.net.SocketException: Network is unreachable
at java.base/sun.nio.ch.DatagramSocketAdaptor.disconnect(DatagramSocketAdaptor.java:136)
at java.base/java.net.DatagramSocket.disconnect(DatagramSocket.java:393)
at jdk.naming.dns/com.sun.jndi.dns.DnsClient.doUdpQuery(DnsClient.java:437)
at jdk.naming.dns/com.sun.jndi.dns.DnsClient.query(DnsClient.java:214)
at jdk.naming.dns/com.sun.jndi.dns.Resolver.query(Resolver.java:81)
at jdk.naming.dns/com.sun.jndi.dns.DnsContext.c_getAttributes(DnsContext.java:434)
at java.naming/com.sun.jndi.toolkit.ctx.ComponentDirContext.p_getAttributes(ComponentDirContext.java:235)
at java.naming/com.sun.jndi.toolkit.ctx.PartialCompositeDirContext.getAttributes(PartialCompositeDirContext.java:141)
at java.naming/com.sun.jndi.toolkit.ctx.PartialCompositeDirContext.getAttributes(PartialCompositeDirContext.java:129)
at java.naming/javax.naming.directory.InitialDirContext.getAttributes(InitialDirContext.java:171)
at com.mongodb.internal.dns.DefaultDnsResolver.resolveAdditionalQueryParametersFromTxtRecords(DefaultDnsResolver.java:114)
at com.mongodb.ConnectionString.<init>(ConnectionString.java:381)
at com.mongodb.client.MongoClients.create(MongoClients.java:61)
at io.my.package.dbsetup.DatabaseService.<init>(DatabaseService.java:28)
When I print the connectionString and run mongo $connectionString in terminal, I can connect with no problems. Even MongoDB Compass works. It's just Gradle that doesn't.
My colleague with Ubuntu (I have a Mac) can connect with no issues when running the same code. What could be causing this? Firewall is off.
Turns out I needed to use different Java version - 16 didn't work, but I had luck with 8

How to fix error "Enrollment failed" when trying WSO2 IoT 3.3.0 android enrollment?

I set up a new server windows 2012R2 in a VM machine. The latest active-mq and Apache-ant are downloaded. Oracle JDK 8u192 is used. After installation and setup of the WSO2 IoT application, I cannot enroll an android device.
I installed the WSO2IOT by following the instructions in the online documentations for version 3.3.0.
CARBON_HOME and JAVA_HOME are set up in environment variables already.
The process of steps that I go are as follows:
I start the activemq by running it inside a cmd window as instructed by the documentation.
I start broker.bat in another cmd window
I start iot-server.bat in another cmd window
I start analytics.bat in another cmd window
Everything starts and I end up with the text "Carbon .. has stared in ** milliseconds.
I open my management console on https port 9443\devicemgt and login as admin no problem.
After that I connect my galaxy A5 2016 model with android 7.0 to the same network via WiFi. Download the app via QR code from my PC screen to the mobile phone. Install the app and try to register. The IP which I enter is static in the VM and of course I add 8280 port in the wso2 management app on the phone. Then I login with admin/admin credentials which logins successfully but right after that it posts an message on the phone that it is receiving policy and here it stops. The little circle spins (loading) and nothing happens for few minutes after which I get an error "Enrollment failed. Contact the administrator. Enrollment failed." no other message or anything.
On the analytics cmd window I got the following error inside my VM:
[2018-12-20 11:00:00,037] [IoT-Analytics] ERROR {org.wso2.carbon.ntask.core.impl.TaskQuartzJobAdapter} - Error in executing task: nulljava.lang.NullPointerException
at org.wso2.carbon.analytics.spark.core.CarbonAnalyticsProcessorService.executeQuery(CarbonAnalyticsProcessorService.java:256)
at org.wso2.carbon.analytics.spark.core.CarbonAnalyticsProcessorService.executeScript(CarbonAnalyticsProcessorService.java:206)
at org.wso2.carbon.analytics.spark.core.AnalyticsTask.execute(AnalyticsTask.java:60)
at org.wso2.carbon.ntask.core.impl.TaskQuartzJobAdapter.execute(TaskQuartzJobAdapter.java:67)
at org.quartz.core.JobRunShell.run(JobRunShell.java:213)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
And that is basically it I cant move on forward from here. I tried with different java jdk versions as old as 8u144 and I tried with openJDK 8 LTSu191 to no avail.
Other things like creating policies in the devicemgt portal, creating users and browsing the portal works fine.
Did anyone encounter this issue and manage to solve it?
Thanks.
I used WM windows10. The situation fully corresponded to that described by you, with only one difference - I also had an error on the page with the preservation of policies for Android. I also saw that the default policies for windows are reflected in the platform configuration section, and the android policies are missing and cannot be saved due to the error you described. However, in the wso2 home directory I found the Android configuration file in which the default policy !!! was done.
Next, I used ADB to watch the log from the Android device, at the time of binding (enrollment). He only confirmed the previously received information. I saw a 404 http error at the time the device attempted to get a policy agreement. Point.
Unexpected outcome. I downloaded version 3.1.0 instead of the current version 3.3.0. I started the batch file. I went to the platform configuration section, to the Android configuration - the default agreement policy was displayed correctly and you can change it and save the changes. The binding procedure (enrollment) passed without problems - the policy was obtained by the device and then everything went according to official instructions. I fully realize that this is not the answer to the question you raised, but at the same time it can help with a quick start. I hope.
p.s. I tried versions 3.3.1 and 3.3.0 - in both there is a similar problem with the enrollment. Version 3.1.0 does not have this problem. Versions tested on Ubuntu and WM Windows10.
Of course it would be great if the developer representatives tell you where to dig, to use a more current version. Have a nice day.
additionaly - also good work with 3.2.0

Derby authentication error from Glassfish console but same credentials work from ij

I am trying, for the first time, to run a java EE 7 web app without an IDE and struggling through the learning curve. To keep things simple I have started with Glassfish 4.1 and Derby 10.11.1.2 which is what I used for development.
My current problem is an error configuring the connection pool on the Glassfish web interface. The error is 'Connection authentication failure occurred. Reason: Userid or password invalid'. However I have ij runing in a dos prompt and the Glashfish web console in Chrome.
from ij I can type 'connect 'jdbc:derby:localhost:1527/databasename;user=username;password=password'; and I connect fine and can look at tables, etc. In the Glassfish web console I have name/value pairs with the same 'user' and 'password' values and it fails (exact same letters & case). I've tried changing the 'databaseName' property to make sure the error wasn't misleading and confirmed it has found the database correctly.
At face value, the error message seems wrong as I have proven from the DOS window. I am sure I am doing something wrong but am lost at how to diagnose it. Any suggestions?
More details of the steps taken: (Although I am sure some of these steps superceed others my lack of success has me in the mindset that redundancy is better than omission - all-in-all it seems much more complicated than it needs to be for a basic setup). My target is Wildfly but Glassfish documentation is better so I figured I would start there.
relevant Windows environment variables:
JAVA_HOME=C:\Program Files\Java\jdk1.8.0_40
DERBY_HOME=%JAVA_HOME%\db
DERBY_INSTALL=%DERBY_HOME%
JAVADB_HOME=%DERBY_HOME%
GLASSFISH=C:\Program Files\Java\GlassFish-4.1
Path=%JAVA_HOME%\bin;%DERBY_HOME%\bin;%GLASSFISH%\bin;%GLASSFISH%\glassfish
CLASSPATH=%DERBY_HOME%\lib\derbynet.jar;%DERBY_HOME%\lib\derbytools.jar;%DERBY_HOME%\derbyclient.jar;%DERBY_HOME%\lib\derbyrun.jar
WILDFLY_HOME=C:\program files\java\wildfly\8.2.0.Final
sysinfo shows all the right paths and versions
Copied many of the derby jars from %derby_home%\lib to %glassfish%\glassfish\domains\domain1\lib\ext per a post by BalusC. I think classpath duplicates this it but can't hurt
Started Domain 'asadmin start-domain' defaulting to domain 1
Started DB by changing directories and using java. Wanted to use 'asadmin start-database --dbhome DB path' but this always started the wrong version. Glassfish and JDK both package derby/javadb and I couldn't figure out how to upgrade Glassfish or start the correct version any other way
cd \users\john\.netbeans-derby (root of the DB created by Netbeans)
Java –jar “%derby_home%\lib\derbyrun.jar" server start
connect browser to 'localhost:4848' to create JDBC connection pool and resource
connection pool: pool name=connectionPool, resource type=javax.sql.DataSource, DB driver Vendor=Derby, introspect was not enabled (found very little documentation to explain what it is) - step 2 was left as defaults
editing connectionPool - enabled Ping on General tab to identify errors, Additional Properties tab: changed User to DB username, left other attributes as default, added... password=db password, databaseName=ClubScoring
errors were presented along the way which prompted setting each attribute. No error was presented for lack of URL but tested steps below with and without URL=jdbc:derby://localhost:1527/ClubScoring
jdbc resources. Added jdbc/ClubScoring, pool=connectionPool => selected and enabled
starting db from correct directory using 'asadmin start-database' does let the application find the correct DB but it crashes since the DB was created with version 10.11.1.2 and this command starts the Glassfish version of 10.10.2.0
Sorry for making this so long but I haven't found anywhere that lays out all of the steps in a simple fashion and figured the details would save time in the long run.
I was dealing with this issue today and found a solution:
https://db.apache.org/derby/docs/10.14/ref/rrefattribsecmech.html
Basically the only security options allowable (as far as 10.14 is concerned) is 3, 4 and 9.
4 is the default and means "Just UserID". You would think this means that as long as a UserID is given, you could connect. But having both set appears to be an issue.
In order to use a (clear text) password and userID, you have to specify 3. It works also if the attribute is deleted or 0 as well but I don't think you get any security that way.

Java EE 7 updatetool installation fails

I have tried to install Java EE 7 with updatetool to be able to run Java EE Tutorial examples.
But the installation of updatetool fails. I have tried to start updatetool installation from the command line on my elementary os, then I saw the error when installing updatetool.
Here is an image: http://oi58.tinypic.com/x6iumx.jpg
Error text example 1:
Input/output error: Connection failed for URL http://pkg.oracle.com/javaeesdk/7/native/release/manifest/0/updatetool#2.3.5%2C0-56.2852%3A20111207T211721Z: 503: Service Temporarily Unavailable
Could not download application packages. This could be because:
- a proxy server is needed to access the internet. Please ensure that
the system proxy server settings are correct, or set the 'http_proxy'
environment variable to the full URL of the proxy server.
- the package server or network connection is slow.
If you are getting time out errors you can try setting the
PKG_CLIENT_CONNECT_TIMEOUT and PKG_CLIENT_READ_TIMEOUT
environment variables and try again. For example to increase
the timeouts to 300 seconds set them to 300
- the package server is down or otherwise inaccessible or it is
generating invalid data. Please contact the provider of the package
server.
Error text example 2:
File 138/564 Input/output error: Connection failed for URL http: //pkg.oracle.com/javaeesdk/7/native/release/file/0/217e83782a91f09fa7f35122412cd155263b107f: 502: Proxy Error
Could not download application packages. This could be because:
- a proxy server is needed to access the internet. Please ensure that
the system proxy server settings are correct, or set the 'http_proxy'
environment variable to the full URL of the proxy server.
- the package server or network connection is slow.
If you are getting time out errors you can try setting the
PKG_CLIENT_CONNECT_TIMEOUT and PKG_CLIENT_READ_TIMEOUT
environment variables and try again. For example to increase
the timeouts to 300 seconds set them to 300
- the package server is down or otherwise inaccessible or it is
generating invalid data. Please contact the provider of the package
server.
I don't use any proxy server. Help please!
I had the same - it's because their site is so unbelievably slow.
The output you showed tells you what to do, increase the timeout.
But sometimes it just needs to be run again, which worked in my case.
You can download the tutorial from Oracle Java EE 7 SDK download page.
Just download the latest Java EE 7 SDK, and unzip. The tutorial is inside the glassfish4/docs folder.
I have managed to install updatetool finally, after 3 days.
My advice for everyone who has the same problem:
Try installation several times in the morning, afternoon, evening and at night. And maybe once you will have successful attempt :)
The problem was not on my side.

com.mysql.jdbc.exceptions .jdbc4.CommunicationsException: Communications link failure

I have a java plugin to an application that I'm using (I didn't write it and don't have the source) that connects to my MySQL database...the only problem is that anytime I try to load the application I get a communication link failure
17:51:57 [INFO] Could not create connection: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
17:51:57 [INFO] Database initialization failed: java.lang.NullPointerException
I have verified that all of my mysql settings are pointing to the correct port that I'm giving this plugin and I've also checked to make sure the user I created for this has privileges over the database it's going to be modifying. I'm out of ideas and it never times out, I would think it was the plugin but the plugin has many users and they use the plugin with MySQL just fine and I continue to have the problem after reinstalling the plugin.
I'm sure it's an issue with MySQL but as far as I can tell...everything is fine, so any clues about what would cause this would be great. I've been reading around and the stuff I've seen didn't help the issue.
SOLUTION
for UBUNTU and MySQL 5.1: Added mysqld : ALL to /etc/hosts.allow
for UBUNTU and MySQL 5.1: Added mysqld : ALL to /etc/hosts.allow

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