Environment is Red Hat, Cassandra 2.1, Datastax Java driver 2.1.1.
I have developed custom authentication/authorization plugins for Cassandra, and they work beautifully when I try them with cqlsh - I can see my plugins being called, users are authenticated/authorized accordingly, etc. - bottom line, everything works exactly as expected.
Then I tried to test using the Datastax driver. I'm connecting to Cassandra with:
public class CassandraConnection {
private final Cluster cluster;
private final Session session;
public CassandraConnection(final String node, final int port) {
this.cluster = Cluster.builder()
.addContactPoint(node)
.withPort(port)
.withCredentials("someuser", "somepassword")
.build();
this.session = cluster.connect();
}
// Etc....
The call to cluster.connect() generates an exception:
Exception in thread "main" com.datastax.driver.core.exceptions.NoHostAvailableException: All host(s) tried for query failed (tried: localhost/127.0.0.1:9042 (com.datastax.driver.core.TransportException: [localhost/127.0.0.1:9042] Cannot connect))
at com.datastax.driver.core.ControlConnection.reconnectInternal(ControlConnection.java:196)
at com.datastax.driver.core.ControlConnection.connect(ControlConnection.java:80)
at com.datastax.driver.core.Cluster$Manager.init(Cluster.java:1145)
at com.datastax.driver.core.Cluster.init(Cluster.java:149)
at com.datastax.driver.core.Cluster.connect(Cluster.java:225)
at com.<company...packages...>.CassandraConnection.<init>(CassandraConnection.java:21)
Here is the puzzling part: although I can see my plugins being called when I test them using cqlsh, they are never accessed when I use the Datastax driver - I have added log messages in the beginning of each method, and they are never called. There are no errors in the logs indicating any sort of initialization problem, and I do see a message indicating that my plugins will be used.
That exact same client code works with no problem when:
I don't have my plugin running.
I use Cassadra's PasswordAuthenticator.
So, it looks like there is some problem with my plugins, but how can that be if 1) they work fine with cqlsh and 2) none of their methods are being called when the datastax driver is being used?
A couple of additional points - if I try to connect using Datastax's DevCenter, I see the same behavior as my client, with the exact same exception, so that rules out my (very simple) client code. I have also tried to:
cluster.getConfiguration().getSocketOptions().setReadTimeoutMillis(10000);
before calling connect() as suggested in other posts, but that didn't help either - when I step through the client with the debugger, I see the error as soon as I call cluster.connect(), so it's not a time out issue either.
Any help is appreciated.
Related
I have this code
#Bean
public CqlSession getCqlSession() {
return CqlSession.builder()
.addContactPoint(new InetSocketAddress(cassandraHost, cassandraPort))
.withAuthCredentials(cassandraUsername, cassandraPassword)
.build();
}
The connection is failing with this exception:
Failed to instantiate [com.datastax.oss.driver.api.core.CqlSession]: Factory method 'getCqlSession' threw
exception; nested exception is com.datastax.oss.driver.api.core.AllNodesFailedException: Could not reach
any contact point, make sure you've provided valid addresses (showing first 1 nodes, use getAllErrors()
for more): Node(endPoint=tinyurl-cassandra.cassandra.cosmos.azure.com/52.230.23.170:10350, hostId=null,
hashCode=237f706): [com.datastax.oss.driver.api.core.DriverTimeoutException: [s0|control|id: 0xb89dacff,
L:/192.168.0.101:59158 - R:tinyurl-cassandra.cassandra.cosmos.azure.com/52.230.23.170:10350] Protocol
initialization request, step 1 (OPTIONS): timed out after 5000 ms]
I am new to Cassandra and have tried the following:
Validated that the credentials are okay.
Try with csqlsh - could not connect as well.
Check there's no firewall setup in my machine. Can telnet to host and port.
Can open Cassandra Shell from Azure Data Explorer.
What am I missing? I am new to this. Any help will be appreciated.
Looks like you are using the v.4x version of the Java Driver. The default load balancing in this driver mandates that you provide local data center, e.g:
CqlSession.builder().withSslContext(sc)
.addContactPoint(new InetSocketAddress(cassandraHost, cassandraPort)).**withLocalDatacenter("UK South")**
.withAuthCredentials(cassandraUsername, cassandraPassword).build();
You could take a look at this getting started sample for further reference: https://github.com/Azure-Samples/azure-cosmos-db-cassandra-java-getting-started-v4
I am attempting to instrument JDBC calls using the Kamon JDBC Kanela agent in my Spark app.
I am able to successfully instrument JDBC calls in a non-spark test app by passing in -javaagent:kanela-agent-1.0.1.jar on the command line when I run the app from the JAR. When I do this, I see the Kanela banner display in the console, and can see that my failed statement processor is getting called when there is a SQL error.
From my research, I should be able to inject a javaagent into the executor of a Spark app by passing in the following to spark-submit: --conf "spark.executor.extraJavaOptions=-javaagent:kanela-agent-1.0.1.jar". However, when I do this, although the Kamon banner IS displaying on the console upon my call to Kamon.init(), my failed statement processor is NOT getting called when there is a SQL error.
Things I'm wondering:
Is there something about the way that spark-jdbc makes these JDBC calls that would prevent a javaagent from "seeing" them?
Does my call to Kamon.init() somehow only apply to code in the Spark driver, and not the executor?
Any other reason that you can think of that would be preventing this from working?
thanks for the time. I am trying to access a remote Cassandra DB in order to complete my assertions. I see that the Server is running:
Cassandra V 3.0.8.1293
Driver Type: Cassandra CQL
Datastax Java Driver for Apache Cassandra - Core [3.0.5]
So, I am trying with the following simple code to access the DB
import com.datastax.driver.core.*
Cluster cluster = null;
try {
cluster = Cluster.builder().addContactPoint("x.x.x.x").withCredentials("xxxxxxx", "xxxxxx").withPort(9042).build()
Session session = cluster.connect();
ResultSet rs = session.execute("select * from TABLE");
Row row = rs.one();
} finally {
if (cluster != null) cluster.close();
}
when I use the cassandra-driver-core-2.0.1.jar I am getting the error :
ERROR:com.datastax.driver.core.exceptions.NoHostAvailableException: All host(s) tried for query failed (tried: /x.x.x.x(null))
Read the documentation and a lot of posts here and on other blogs and I saw that there may be an incompatibility with the driver version so I tried to upgrade the driver to many versions (cassandra-driver-core-2.5,cassandra-driver-core-3,cassandra-driver-core-3.2), but on that I am getting the following:
ERROR:java.lang.ExceptionInInitializerError
Have also tried to connect using JDBC, but to no avail, using the configuration proposed at this thread
SoapUI JDBC connection with Apache Cassandra
Actually I am running out of ideas. Can anyone propose or point to some direction on how to actually achieve this, either by pointing me to some tutorial or any idea.
Thank you very much
I think you haven't enable remote access to cassandra.
Try enabling remote access using below configuration -
File Path /etc/cassandra/default.conf/cassandra.yaml
rpc_address: 0.0.0.0
broadcast_rpc_address: <serverIPAddress>
After that, restart cassandra service.
I am trying to insert data into sql server using spark using the below Jdbc methods.
Option 1:
prop.put("driver", "com.microsoft.sqlserver.jdbc.SQLServerDriver")
dataf.write.mode(org.apache.spark.sql.SaveMode.Append).jdbc(url,table_name, prop)
Table is already created. Appending new data.Job Error-ed with the below exception
Exception in thread "main"
com.microsoft.sqlserver.jdbc.SQLServerException: CREATE TABLE
permission denied in database
Question is : Why create table permission is required for appending the data?
Option2:
prop.put("driver", "com.microsoft.sqlserver.jdbc.SQLServerDriver")
org.apache.spark.sql.execution.datasources.jdbc.JdbcUtils.saveTable(dataf, url, table_name, prop)
Above command working from spark-shell. when the same is used in scala code and packaged with dependencies giving below exception
Exception in thread "main" java.sql.SQLException: No suitable driver
at java.sql.DriverManager.getDriver(DriverManager.java:315)
I tried setting driver class-path and executor class-path and also --jars still no luck. Included sqljdbc4.jar in driver-classpath and --jars.
Copied sqljdbc4.jar to all worker nodes as well still no luck.
Any Ideas on this?
After Lot of searching and Testing, I found the answer. It might be useful for someone.
Option 1: This is because of bug in spark 1.5.X. the same was resolved
in 1.6.x and later. Because of the bug, It always try to create a new
table.
Option2: This causes because , driver name on classpath given
priority than properties we are passing as argument. Workaround for
this is to create connection and then invoke savetable.
workaround if you are using spark 1.5.x or lower.
JdbcUtils.createConnection(url, prop)
JdbcUtils.saveTable()
I have a Spring Boot Application that uses Spring Data for Cassandra. One of the requirements is that the application will start even if the Cassandra Cluster is unavailable. The Application logs the situation and all its endpoints will not work properly but the Application does not shutdown. It should retry to connect to the cluster during this time. When the cluster is available the application should start to operate normally.
If I am able to connect during the application start and the cluster becomes unavailable after that, the cassandra java driver is capable of managing the retries.
How can I manage the retries during application start and still use Cassandra Repositories from Spring Data?
Thanx
It is possible to start a Spring Boot application if Apache Cassandra is not available but you need to define the Session and CassandraTemplate beans on your own with #Lazy. The beans are provided out of the box with CassandraAutoConfiguration but are initialized eagerly (default behavior) which creates a Session. The Session requires a connection to Cassandra which will prevent a startup if it's not initialized lazily.
The following code will initialize the resources lazily:
#Configuration
public class MyCassandraConfiguration {
#Bean
#Lazy
public CassandraTemplate cassandraTemplate(#Lazy Session session, CassandraConverter converter) throws Exception {
return new CassandraTemplate(session, converter);
}
#Bean
#Lazy
public Session session(CassandraConverter converter, Cluster cluster,
CassandraProperties cassandraProperties) throws Exception {
CassandraSessionFactoryBean session = new CassandraSessionFactoryBean();
session.setCluster(cluster);
session.setConverter(converter);
session.setKeyspaceName(cassandraProperties.getKeyspaceName());
session.setSchemaAction(SchemaAction.NONE);
return session.getObject();
}
}
One of the requirements is that the application will start even if the Cassandra Cluster is unavailable
I think you should read this session from the Java driver doc: http://datastax.github.io/java-driver/manual/#cluster-initialization
The Cluster object does not connect automatically unless some calls are executed.
Since you're using Spring Data Cassandra (that I do not recommend since it has less feature than the plain Mapper Module of the Java driver ...) I don't know if the Cluster object or Session object are exposed directly to the users ...
For retry, you can put the cluster.init() call in a try/catch block and if the cluster is still unavaible, you'll catch an NoHostAvailableException according to the docs. Upon the exception, you can schedule a retry of cluster.init() later