Mateusz Łyczek created HADOOP-18174:
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Summary: IBM Java detected while running on OpenJDK class library
Key: HADOOP-18174
URL: https://issues.apache.org/jira/browse/HADOOP-18174
Project: Hadoop Common
Issue Type: Bug
Affects Versions: 3.3.2
Reporter: Mateusz Łyczek
In our project we are using hadoop-client library and everything works fine
while running inside containers with official OpenJDK base image.
But for optimisation purposes we also use ibm-semeru-runtimes base images
([https://www.ibm.com/support/pages/semeru-runtimes-release-notes] ). To be
specific we use *open-17.0.1_12-jre* version of this image and encountered the
following problem.
Our application is throwing an exception while using hadoop-client to upload
files:
{code:java}
failure to login: javax.security.auth.login.LoginException: No LoginModule
found for com.ibm.security.auth.module.JAASLoginModule{code}
After a little investigation I found that this login module is selected by
Hadoop only when it detects that it is being run on IBM Java (see
[https://github.com/apache/hadoop/blob/672e380c4f6ffcb0a6fee6d8263166e16b4323c2/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java#L434]
)
{code:java}
private static String getOSLoginModuleName() {
if (IBM_JAVA) {
return "com.ibm.security.auth.module.JAASLoginModule";
} else {
return windows ? "com.sun.security.auth.module.NTLoginModule"
: "com.sun.security.auth.module.UnixLoginModule";
}
} {code}
and IBM Java is detected base on *java.vendor* system property value (see
[https://github.com/apache/hadoop/blob/672e380c4f6ffcb0a6fee6d8263166e16b4323c2/hadoop-common-project/hadoop-auth/src/main/java/org/apache/hadoop/util/PlatformName.java#L50]
)
{code:java}
/**
* The java vendor name used in this platform.
*/
public static final String JAVA_VENDOR_NAME =
System.getProperty("java.vendor");
/**
* A public static variable to indicate the current java vendor is
* IBM java or not.
*/
public static final boolean IBM_JAVA = JAVA_VENDOR_NAME.contains("IBM");
{code}
I checked inside the ibm-semeru-runtimes based version of our docker container
and the *java.vendor* system property is set to the following value:
{code:java}
java.vendor: IBM Corporation {code}
but, as the documentation for IBM Semeru runtimes images says, it contains
OpenJDK class libraries with Eclipse OpenJ9 JVM. I confirmed it by running
{*}java -version{*}:
{code:java}
openjdk version "17.0.1" 2021-10-19
IBM Semeru Runtime Open Edition 17.0.1.0 (build 17.0.1+12)
Eclipse OpenJ9 VM 17.0.1.0 (build openj9-0.29.1, JRE 17 Linux amd64-64-Bit
Compressed References 20211207_75 (JIT enabled, AOT enabled)
OpenJ9 - 7d055dfcb
OMR - e30892e2b
JCL - fc67fbe50a0 based on jdk-17.0.1+12) {code}
therefore there is no {{com.ibm.security.auth.module.JAASLoginModule}} class
present.
Therefore I would like to ask if there is any other way of detecting IBM java
instead of checking the *java.vendor* system property, that would be more
accurate?
I tried to think about something to suggest - the first thing that came to my
mind was to check if one of the classes from IBM packages actually exists by
trying to load it but I don't know the other usages of the *IBM_JAVA* variable
in hadoop-client, to be sure that it's a good idea for you.
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