org.apache.cassandra.locator.Ec2Snitch Maven / Gradle / Ivy
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package org.apache.cassandra.locator;
import java.io.DataInputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.InetAddress;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.db.SystemKeyspace;
import org.apache.cassandra.exceptions.ConfigurationException;
import org.apache.cassandra.gms.ApplicationState;
import org.apache.cassandra.gms.EndpointState;
import org.apache.cassandra.gms.Gossiper;
import org.apache.cassandra.io.util.FileUtils;
import org.apache.cassandra.utils.FBUtilities;
/**
* A snitch that assumes an EC2 region is a DC and an EC2 availability_zone
* is a rack. This information is available in the config for the node.
*/
public class Ec2Snitch extends AbstractNetworkTopologySnitch
{
protected static final Logger logger = LoggerFactory.getLogger(Ec2Snitch.class);
protected static final String ZONE_NAME_QUERY_URL = "http://169.254.169.254/latest/meta-data/placement/availability-zone";
private static final String DEFAULT_DC = "UNKNOWN-DC";
private static final String DEFAULT_RACK = "UNKNOWN-RACK";
private Map> savedEndpoints;
protected String ec2zone;
protected String ec2region;
public Ec2Snitch() throws IOException, ConfigurationException
{
String az = awsApiCall(ZONE_NAME_QUERY_URL);
// Split "us-east-1a" or "asia-1a" into "us-east"/"1a" and "asia"/"1a".
String[] splits = az.split("-");
ec2zone = splits[splits.length - 1];
// hack for CASSANDRA-4026
ec2region = az.substring(0, az.length() - 1);
if (ec2region.endsWith("1"))
ec2region = az.substring(0, az.length() - 3);
String datacenterSuffix = (new SnitchProperties()).get("dc_suffix", "");
ec2region = ec2region.concat(datacenterSuffix);
logger.info("EC2Snitch using region: {}, zone: {}.", ec2region, ec2zone);
}
String awsApiCall(String url) throws IOException, ConfigurationException
{
// Populate the region and zone by introspection, fail if 404 on metadata
HttpURLConnection conn = (HttpURLConnection) new URL(url).openConnection();
DataInputStream d = null;
try
{
conn.setRequestMethod("GET");
if (conn.getResponseCode() != 200)
throw new ConfigurationException("Ec2Snitch was unable to execute the API call. Not an ec2 node?");
// Read the information. I wish I could say (String) conn.getContent() here...
int cl = conn.getContentLength();
byte[] b = new byte[cl];
d = new DataInputStream((FilterInputStream) conn.getContent());
d.readFully(b);
return new String(b, StandardCharsets.UTF_8);
}
finally
{
FileUtils.close(d);
conn.disconnect();
}
}
public String getRack(InetAddress endpoint)
{
if (endpoint.equals(FBUtilities.getBroadcastAddress()))
return ec2zone;
EndpointState state = Gossiper.instance.getEndpointStateForEndpoint(endpoint);
if (state == null || state.getApplicationState(ApplicationState.RACK) == null)
{
if (savedEndpoints == null)
savedEndpoints = SystemKeyspace.loadDcRackInfo();
if (savedEndpoints.containsKey(endpoint))
return savedEndpoints.get(endpoint).get("rack");
return DEFAULT_RACK;
}
return state.getApplicationState(ApplicationState.RACK).value;
}
public String getDatacenter(InetAddress endpoint)
{
if (endpoint.equals(FBUtilities.getBroadcastAddress()))
return ec2region;
EndpointState state = Gossiper.instance.getEndpointStateForEndpoint(endpoint);
if (state == null || state.getApplicationState(ApplicationState.DC) == null)
{
if (savedEndpoints == null)
savedEndpoints = SystemKeyspace.loadDcRackInfo();
if (savedEndpoints.containsKey(endpoint))
return savedEndpoints.get(endpoint).get("data_center");
return DEFAULT_DC;
}
return state.getApplicationState(ApplicationState.DC).value;
}
}