关于hadoop登陆kerberos时设置环境变量问题的思考

package demo.kerberos;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.security.UserGroupInformation;

public class KerberosLoginTest {

	public static void main(String[] args) throws IOException {
		// 设置kerberos相关登陆信息
		// 方法1：设置krb5.conf配置文件
		System.setProperty("java.security.krb5.conf", "/home/eabour/hadoop/conf/krb5.conf");
		// 方法2：设置kerberos环境变量
		// System.setProperty("java.security.krb5.realm", "HADOOP.COM");
		// System.setProperty("java.security.krb5.kdc", "kdc.server.com");
		// 开启登陆调试日志
		System.setProperty("sun.security.krb5.debug", "true");
		Configuration conf = new Configuration();
		conf.addResource(new Path("/home/eabour/hadoop/conf/core-site.xml"));
		conf.addResource(new Path("/home/eabour/hadoop/conf/hdfs-site.xml"));
		UserGroupInformation.setConfiguration(conf);
		// 登陆kerberos
		UserGroupInformation.loginUserFromKeytab("test@HADOOP.COM", "/home/eabour/test.keytab");
		// TODO
		// 访问HDFS
	}

}

    /**
     * Private constructor - can not be instantiated externally.
     */
    private Config() throws KrbException {
        /*
         * If either one system property is specified, we throw exception.
         */
        String tmp = getProperty("java.security.krb5.kdc");
        if (tmp != null) {
            // The user can specify a list of kdc hosts separated by ":"
            defaultKDC = tmp.replace(‘:‘, ‘ ‘);
        } else {
            defaultKDC = null;
        }
        defaultRealm = getProperty("java.security.krb5.realm");
        if ((defaultKDC == null && defaultRealm != null) ||
            (defaultRealm == null && defaultKDC != null)) {
            throw new KrbException
                ("System property java.security.krb5.kdc and " +
                 "java.security.krb5.realm both must be set or " +
                 "neither must be set.");
        }

        // Always read the Kerberos configuration file
        try {
            Vector<String> configFile;
            String fileName = getJavaFileName();
            if (fileName != null) {
                configFile = loadConfigFile(fileName);
                stanzaTable = parseStanzaTable(configFile);
                if (DEBUG) {
                    System.out.println("Loaded from Java config");
                }
            } else {
                boolean found = false;
                if (isMacosLionOrBetter()) {
                    try {
                        stanzaTable = SCDynamicStoreConfig.getConfig();
                        if (DEBUG) {
                            System.out.println("Loaded from SCDynamicStoreConfig");
                        }
                        found = true;
                    } catch (IOException ioe) {
                        // OK. Will go on with file
                    }
                }
                if (!found) {
                    fileName = getNativeFileName();
                    configFile = loadConfigFile(fileName);
                    stanzaTable = parseStanzaTable(configFile);
                    if (DEBUG) {
                        System.out.println("Loaded from native config");
                    }
                }
            }
        } catch (IOException ioe) {
            // No krb5.conf, no problem. We‘ll use DNS or system property etc.
        }
    }

kdc=kdc.server.com:88

kdc=kdc.server.com:1088

[realms]
    HADOOP.COM = {
    kdc = kdc.server.com:1088
}

System.setProperty("java.security.krb5.kdc", "kdc.server.com:1088");