I have successfully setup ndbcluster version 7.1.26.
This contains 2 data nodes[NDBD], 2 mysql [MYSQLD] nodes and one management [MGMD] node.
Replication works successfully.
My Web application is deployed in JBoss-5.0.1 and using JNDI for connection resources which are specified in application specific ds.xml file in load balanced url forms e.g. jbdc:mysql:loadbalance:host1:port1,host2:port2/databaseName.
host1 : refers to first mysqld node and port1 refers the port it is running on.
host2 : refers to second mysqld node and port2 refers the port it is running on.
When both of the [MySQLD] nodes are up and running everything works fine and cluster responds well, replicates data, and data retrieval operations also work properly.
But issues are raised when any of the [MySQLD] nodes goes down. Data gets inserted/updated/replicated but the application is unable to retrieve data from cluster and web page remains busy working which means busy retrieving data. As soon as the node which was down goes up it responds properly and application goes forward and shows up data retrieved from cluster.
At JBoss 5.0.1 startup it showed up a NullPointerException in class LoadBalancingConnectionProxy.invoke(LoadBalancingConnectionProxy.java:439). Tell me if the above Exception plays any role in the above explained issues.
If anyone had faced issues like above and if has any solution regarding the issues please let me know.
Thanks and regards.
I have resolved the issue as it was a bug in the connectorJ's version.
As The project I am working on was already using both the buggy jar mysql-connector-java-5.0.8.jar and the jar version in which the issue is already resolved i.e. mysql-connector-java-5.1.13-bin.jar.
After all the search when I removed the jar mysql-connector-java-5.0.8.jar my issues got resolved.
All that was problematic was that the ConnectorJ/Driver was getting referred from the buggy jar.
The bug id and url which refers to this issue is:
http://bugs.mysql.com/bug.php?id=31053
.
Thanks for considerations.
Are you using different userids and passwords for each of the hosts(host1, host2) specified in the tag ? (Either directly or using tag) ?
Related
I've nearly got a SpringBoot app running on Google Cloud services that is connected to a Postgres instance.
I've ran through the steps on their guide, located here and have gotten to the point where I need to set my variables up for the app to find the database instance:
The problem encountered is two fold:
I don't know where and how to set these
My server logs report this error:
meaning that the Spring application is trying to find the database like it would on my local.
I set the following values in the app.yaml (assuming this is where they should be?)
runtime: java11
instance_class: F1
env_variables:
SQL_USER: quickstart-user
SQL_PASSWORD: <password>
SQL_DATABASE: quickstart_db
INSTANCE_CONNECTION_NAME: quickstart-instance
So, my question(s) are:
Is this the correct place to set them?
If not, do I need a appengine-web.xml file instead (And does anyone have an example of what this looks like, I can't find one)
How do I stop the app from looking for the local database?
Thanks
In the PostgreSQL documentation https://www.postgresql.org/docs/10/libpq-connect.html, it has been said that multiple hosts can be specified in a single connection string such that all the hosts will be tried in order one after the other until one of the server gets succeeds.
But when i tried to implement the same setting in the tag present in my ASP.net web.config file, it is throwing error as no such host name. I am using NpgSQL provider in order to connect to PostgreSQL database.
I need to add multiple server names in the connection string such that if the server#1 fails then it should try for the next server server#2 immediately provided in the order until it succeeds
Can you please suggest on how multiple hosts can be provided in the connection string?
The Npgsql driver does not currently support this functionality. The issue tracking this is https://github.com/npgsql/npgsql/issues/732, I'm still hoping we can get this into the next release but there's a lot going on.
Load balancing and failover is avaialble in Npgsql version 6. At the time of writing v.6 is in preview.
Simple failover example (server2 is only used if a connection could not be established to server1):
Host=server1,server2;Username=test;Password=test
Example with load balancing (round robin I guess):
Host=server1,server2,server3,server4,server5;Username=test;Password=test;Load
Balance Hosts=true;Target Session Attributes=prefer-standby
https://www.npgsql.org/doc/failover-and-load-balancing.html
I am trying to deploy a simple web application written using Play Framework in Scala to Amazon web service.
The web application is running OK in development mode and production mode in my local machine, and I've changed its default port to 80.
I used Boxfuse to deploy to AWS as suggested.
I first run "sbt dist"
then "boxfuse run -env=prod"
Things went well as desired. The image is fused and pushed to AWS. AMI is created. Instance was started and my application was running.
i-0f696ff22df4a2b71 => 2017-07-13 01:28:23.940 [info] play.api.Play - Application started (Prod)
Then came the error message:
WARNING: Healthcheck (http://35.156.38.90/) returned 400 instead of 200. Retrying for the next 300 seconds ...
i-0f696ff22df4a2b71 => 2017-07-13 01:28:24.977 [info] p.c.s.AkkaHttpServer - Listening for HTTP on /0.0.0.0:80
i-0f696ff22df4a2b71 => 2017-07-13 01:28:25.512 [warn] p.f.h.AllowedHostsFilter - Host not allowed: 35.156.38.90
The instance was terminated after repeated try after 3 minutes. It gave a warning like:
Ensure your application responds with an HTTP 200 at / on port 80
But I've made sure the application responds in local machine, and I tried both Windows and Ubuntu, all works well.
Also, running "boxfuse run" on local machine, I can connect to it using "http://localhost", but still have the error.
Hope someone with experience can give me some suggestions. Thanks in advance.
ps: not sure if relevant, I added these settings to application.conf
http {
address = 0.0.0.0
port = 80
}
Judging from the error message, it looks like the problem might be related to play.filters.hosts.allowed not set up in application.conf. The filter lets you configure which hosts can access your application. More details about the Play filter is available here.
Here's a configuration example:
play.filters.hosts {
allowed = ["."]
}
Note that allowed = ["."] matches all hosts hence would not be recommended in a production environment.
As stated in the Boxfuse Play Documentation:
If your application uses the allowed hosts filter you must ensure play.filters.hosts.allowed in application.conf allows connections from anywhere as this filter otherwise causes ELB healthchecks to fail. For example:
play.filters.hosts {
allowed = ["."]
}
More info in the official Play documentation.
I'm working on a coreaudio user-space hal plugin based on the example
developer.apple.com/library/mac/samplecode/AudioDriverExamples/Introduction/Intro.html
In the plug-in implementation, I plan to obtain audio data from another process i.e. CFMessagePort
However, I got the following error in console trying to create port CFMessagePortCreateLocal...
sandboxd[251]: ([2597]) coreaudiod(2597) deny mach-register com.mycompnay.audio
I did some googlging and came to this article
Technical Q&A QA1811
https://developer.apple.com/library/mac/qa/qa1811/_index.html
about adding AudioServerPlugIn_MachServices in plist but still no success.
Is there anything else I need to do to make this work (like adding entitlements, code-sign) or this is not the correct approach.?
I am not sure if MesssagePort mechanism works anymore under sandbox. would XPC Services be viable?
Thank you very much for your time. Any help is greatly appreciated
update 1:
I should be creating a remote port instead of a local in the audio plug-in. Having that said, with the AudioServerPlugIn_MachServices attribute in the plist. now there is no sandboxd[559]: ([552]) coreaudiod(552) deny mach-lookup / register message in console.
However, in my audio hal plug-in (client side) I have
CFStringRef port_name = CFSTR("com.mycompany.audio.XPCService");
CFMessagePortRef port = CFMessagePortCreateRemote(kCFAllocatorDefault, port_name);
port has return the value of 0. I tried this in a different app and it works just fine.
This is my server side:
CFStringRef port_name = CFSTR("com.mycompany.audio.XPCService");
CFMessagePortRef port = CFMessagePortCreateLocal(kCFAllocatorDefault, port_name, &callback, NULL, NULL);
CFRunLoopSourceRef runLoopSource =
CFMessagePortCreateRunLoopSource(nil, port, 0);
CFRunLoopAddSource(CFRunLoopGetCurrent(),
runLoopSource,
kCFRunLoopCommonModes);
CFRunLoopRun();
I did get a console message regarding this.
com.apple.audio.DriverHelper[1314]: The plug-in named SimpleAudioPlugIn.driver requires extending the sandbox for the mach service named com.mycompnay.audio.XPCService
anyone know why??
update 2
I noticed that when I use the debug mode with coreaudiod it does successful get the object reference of the mach service. (same thing happened when I was trying the xpc_service approach)
project scheme setting
Anyone??
I'm pretty sure I was running into the same problems in my AudioServerPlugIn. I could look up and use every Mach service I tried, except for the ones I had created. And the ones I had created worked normally from a regular process.
Eventually I read the Daemonomicon and figured out that coreaudiod (which hosts the HAL plugins) was using the global bootstrap namespace, but my service was being registered in the per-user bootstrap namespace. And since "processes using the global namespace can only see services in the global namespace" my plugin couldn't see my service.
You can use launchctl to test this by having it run the program that registers your service, but with the same bootstrap namespace as coreaudiod. You'll probably need to have rootless disabled.
# launchctl bsexec $(pgrep coreaudiod) your_service_executable
With that running, try to connect from your plugin again.
From Table 2 in the Daemonomicon, you can see that only launchd daemons use the global bootstrap namespace. That explains why coreaudiod uses it. And I think it means that your Mach service needs to be created by a launchd daemon.
To make one, create a launchd.plist for your service in /Library/LaunchDaemons. Set its owner to root:wheel and make it only writable by the owner. In it, set the MachServices key and add the name of your service:
<key>MachServices</key>
<dict>
<key>com.mycompany.audio.XPCService</key>
<true/>
</dict>
Then register it:
# launchctl bootstrap system /Library/LaunchDaemons/com.mycompany.audio.XPCService.plist
This is what I ended up with: com.bearisdriving.BGM.XPCHelper.plist.template. Note that without the UserName/GroupName keys your daemon will run as root. (The code for my service and plugin is in that repo as well, in case that's helpful.)
I ended up having to use XPC, unfortunately, but I tried CFMessagePort first and it worked fine.
It also seems to all work fine whether the plugin is signed or not. Though, as you say, you do need the AudioServerPlugIn_MachServices key in your Info.plist.
I am trying to use the ElasticSearch module (https://github.com/cleverage/play2-elasticsearch) with my Play 2 application. In the readme, it says I should add the following to my application.conf:
## define local mode or not
elasticsearch.local=false
## list clients
elasticsearch.client="192.168.0.46:9300"
# ex : elasticsearch.client="192.168.0.46:9300,192.168.0.47:9300"
What is local mode? What is my client URL supposed to be? I can not find any information on what these options should be. With my current options, I get a NoNodeAvailableException.
Some people suggest:
elasticsearch.local=false elasticsearch.client=mynode1:9200,mynode2:9200
But what is mynode1 and mynode2? It doesn't work with my application. Can anyone help? Thanks
What is local mode?
If elaticsearch.local=true, a elasticsearch node is started in your application ( embedded )
What is my client URL supposed to be?
It's your host:port, but the port is the tcp transport define on your elasticsearch node.
By default, the port start on 9300 ( http://www.elasticsearch.org/guide/reference/modules/transport.html )
I can not find any information on what these options should be. With my current options, I get a NoNodeAvailableException.
I think you have a problem on port number.
mynode1 and mynode2 are elasticsearch nodes.
Do you have any Elasticsearch node running?
On which IP address?
Can you try to connect on these nodes using curl, for example:
curl localhost:9200
Or
curl YOURIPADDRESS:9200
If one of this is successful, then configure your play app using YOURIPADDRESS:9300 as Nicolas Boire wrote before.
If no one is successful, check that you have installed Elasticsearch and launched it before.
HTH
I've just had the same problem, be sure that you respect the version requirements written in the table : https://github.com/cleverage/play2-elasticsearch
At the beginning, I set up the latest version of the plugin 0.8.1 but my ElasticSearch version was 1.0.2.
By starting ES with version 0.9.13, it worked.