**Affected version:** 7.12 - 7.17.7, 8.0-8.5
**Fixed in:** 7.17.7, 8.5.0

### Problem Description

A continuous transform can fail if a transform is searching at the same time as an ILM action occurs or in general anything that closes an index. This should not happen if transform is configured with a wildcard pattern for the source index, e.g. `filebeat-*`.

In a specific case an ILM policy temporarily closes the index due to the unfollow-the-follower action.

A typical log entry for this bugs contains something like this:

```
task encountered irrecoverable failure: org.elasticsearch.cluster.block.ClusterBlockException: index [ ... ] blocked by: [FORBIDDEN/4/index closed];
```

### Mitigation

A: Restart the transform. This can be automated by monitoring `_stats` and restarting the transform using `_stop?force=true` followed by `_start`.

B: Don't use the ILM unfollow action until a fix is available.

C: **Unreleased**: Starting with 8.5 set the transform to `unattended` mode via `settings`, this will let transform retry even for this failure class

### Solution

If the source of a transform is configured with a wildcard, transform should not treat an index closed exception as an irrecoverable failure.

### Backport

The fix needs to be backported to the `7.17` series.
x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/transforms/TransformFailureHandler.java
* @param settingsConfig The settings
     */
    boolean handleStatePersistenceFailure(Exception e, SettingsConfig settingsConfig) {
        
        
        int numFailureRetries = getNumFailureRetries(settingsConfig);
        final int failureCount = context.incrementAndGetStatePersistenceFailureCount();
        if (numFailureRetries != -1 && failureCount > numFailureRetries) {
            fail(
                "task encountered more than " + numFailureRetries + " failures updating internal state; latest failure: " + e.getMessage()
            );
            return true;
        }
        return false;
    }
    /**
     * Handle the circuit breaking case: A search consumed too much memory and got aborted.
     * <p>
     * Going out of memory we smoothly reduce the page size which reduces memory consumption.
     * <p>
     * Implementation details: We take the values from the circuit breaker as a hint and reduce
     * either based on the circuitbreaker value or a log-scale value.
     *
     * @param circuitBreakingException CircuitBreakingException thrown
     * @param unattended whether the transform runs in unattended mode
     */
    private void handleCircuitBreakingException(CircuitBreakingException circuitBreakingException, boolean unattended) {
        final int pageSize = context.getPageSize();
        double reducingFactor = Math.min(
            (double) circuitBreakingException.getByteLimit() / circuitBreakingException.getBytesWanted(),