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Posted to dev@knox.apache.org by "Larry McCay (JIRA)" <ji...@apache.org> on 2018/01/09 20:30:00 UTC
[jira] [Updated] (KNOX-1165) Knox - Another unnamed CacheManager
already exists in the same VM.
[ https://issues.apache.org/jira/browse/KNOX-1165?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Larry McCay updated KNOX-1165:
------------------------------
Fix Version/s: 1.1.0
> Knox - Another unnamed CacheManager already exists in the same VM.
> ------------------------------------------------------------------
>
> Key: KNOX-1165
> URL: https://issues.apache.org/jira/browse/KNOX-1165
> Project: Apache Knox
> Issue Type: Bug
> Components: KnoxSSO, Server
> Affects Versions: 0.12.0
> Environment: JDK 1.8
> CentOS-6 (64bit)
> Reporter: Ernani Pereira de Mattos Junior
> Priority: Critical
> Labels: patch
> Fix For: 1.1.0
>
>
> PROBLEM:
> Issue is described on the note ""Error:Shiro environment initialization failed" when starting KNOX";
>
> ERROR env.EnvironmentLoader (EnvironmentLoader.java:initEnvironment(146)) - Shiro environment initialization failed
> org.apache.shiro.cache.CacheException: net.sf.ehcache.CacheException: Another unnamed CacheManager already exists in the same VM. Please provide unique names for each CacheManager in the config or do one of following:
> After implementing the solution of creating a new ehcache.xml and reference as <ehcache name="knox-mytopology1"> we still see the issue:
> Caused by: net.sf.ehcache.CacheException: Another CacheManager with same name 'knox-tp' already exists in the same VM. Please provide unique names for each CacheManager in the config or do one of following:
> STEPS TO REPRODUCE:
> When enabling the following parameters:
> <param>
> <name>main.cacheManager</name>
> <value>org.apache.shiro.cache.ehcache.EhCacheManager</value>
> </param>
> <param>
> <name>main.securityManager.cacheManager</name>
> <value>$cacheManager</value>
> </param>
> <param>
> <name>main.ldapRealm.authenticationCachingEnabled</name>
> <value>true</value>
> </param>
> MORE INFO:
> This KNOX-804 was open to solve this same issue but is not documented anywhere, but we can see the coding changes in GitHub.
> -> The issue seems to be a racing condition on the Shiro lib class, in which depending on the processing power of the server there are two threads within the same "if" statement;
> ref: https://github.com/apache/shiro/blob/master/support/ehcache/src/main/java/org/apache/shiro/cache/ehcache/EhCacheManager.java
> 1. The Default constructor only builds the Object, and does not do much:
> /**
> * Default no argument constructor
> */
> public EhCacheManager() {
> }
> 2. Accordingly with shiro documentation:
> /**
> * Initializes this instance.
> * <p/>
> * If a {@link #setCacheManager CacheManager} has been
> * explicitly set (e.g. via Dependency Injection or programmatically) prior to calling this
> * method, this method does nothing.
> * <p/>
> * However, if no {@code CacheManager} has been set, the default Ehcache singleton will be initialized, where
> * Ehcache will look for an {@code ehcache.xml} file at the root of the classpath. If one is not found,
> * Ehcache will use its own failsafe configuration file.
> * <p/>
> * Because Shiro cannot use the failsafe defaults (fail-safe expunges cached objects after 2 minutes,
> * something not desirable for Shiro sessions), this class manages an internal default configuration for
> * this case.
> *
> * @throws org.apache.shiro.cache.CacheException
> * if there are any CacheExceptions thrown by EhCache.
> * @see net.sf.ehcache.CacheManager#create
> */
> public final void init() throws CacheException {
> ensureCacheManager();
> }
> private net.sf.ehcache.CacheManager ensureCacheManager() {
> ***It fails in here.
> }
> 2.1 This is the head of the exception:
> The source of the existing CacheManager is: InputStreamConfigurationSource [stream=java.io.BufferedInputStream@675ffd1d]
> at org.apache.shiro.cache.ehcache.EhCacheManager.ensureCacheManager(EhCacheManager.java:224)
> at org.apache.shiro.cache.ehcache.EhCacheManager.init(EhCacheManager.java:199)
> at org.apache.shiro.util.LifecycleUtils.init(LifecycleUtils.java:45)
> at org.apache.shiro.util.LifecycleUtils.init(LifecycleUtils.java:40)
> 3. Starting from Knox-804, the KnoxCacheManager was introduced.
> public class KnoxCacheManager extends EhCacheManager {
> +
> + public KnoxCacheManager() {
> + setCacheManager(net.sf.ehcache.CacheManager.create());
> + }
> +}
> *Remember that Init() will do nothing if anything in case the setCacheManager is explicitly set.
> ref:
> https://github.com/apache/knox/commit/f9d8e07d768459240c8665f139cc140575dc5216
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