How to Fix Elasticsearch ILM Rollover Alias Errors
Elasticsearch’s ILM (Index Lifecycle Management) is essential for automating time-series data, but misconfigured aliases can trigger frustrating errors like “index.lifecycle.rollover_alias does not point to index”. For teams on Elasticsearch 6.8 (EOL), resolving this quickly is critical to avoid security risks and upgrade blockers. This guide combines basic fixes and advanced engineering steps to solve ILM errors permanently.
Step 1: Identify the Active Write Index
Run this API call to find which index is the current write target:
bash
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GET _cat/aliases/your_alias?v&h=alias,index,is_write_index
Only the index with is_write_index: true is valid for rollovers.
Real-World Example:
A Hyperflex client’s alias 77d281fd-...interactions pointed to 9 indices, but only one had is_write_index: true.
Step 2: Clean Up Conflicting Aliases
Update the alias to remove invalid indices and lock the correct write index:
json
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POST /_aliases
{
"actions": [
{ "remove": { "index": "old_index_1", "alias": "your_alias" }},
{ "add": { "index": "correct_index", "alias": "your_alias", "is_write_index": true }}
]
}
Step 3: Retry the ILM Policy
Force ILM to reprocess the index:
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POST /correct_index/_ilm/retry
Step 4: Check for Legacy Index Templates (Engineer’s Step)
Outdated index templates may auto-generate indices with broken aliases. Audit templates with:
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GET _index_template/*your_template*
Delete or update templates causing conflicts.
Pro Tip: Let Hyperflex audit your templates during upgrades.
Step 5: Verify ILM Policy Conditions
Ensure your policy’s rollover thresholds (e.g., max_size: 50gb) align with actual index sizes:
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GET _ilm/policy/your_policy
Adjust criteria if indices never trigger rollovers.
Pro Tip: Optimize ILM policies for cost efficiency.
Step 6: Force a Manual Rollover (Engineer’s Step)
If ILM remains stuck, manually trigger a rollover:
bash
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POST /your_alias/_rollover
{
"conditions": { "max_age": "30d" }
}
This creates a new index (e.g., ...-000015) and shifts the alias.
Pro Tip: Let us manage ILM for hands-free automation.
Step 7: Confirm the Fix
Validate with the ILM Explain API:
bash
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GET */_ilm/explain
Why Upgrade from Elasticsearch 6.8 (EOL)?
Staying on EOL versions risks:
🔴 Unpatched Security Holes: Critical vulnerabilities like Log4j remain exposed.
🔴 Silent ILM Failures: Policies break without warnings, causing data sprawl.
🔴 Compliance Violations: GDPR/HIPAA fines from outdated infrastructure.
Upgrade to Elasticsearch 7.x/8.x for security, performance, and official support.
FAQ: Elasticsearch ILM & Aliases
Q: How do I check alias health?
A: Use GET _cat/aliases/your_alias—only one index should have is_write_index: true.
Q: Can I fix ILM without downtime?
A: Yes! Follow Steps 1-7 for zero disruption.
Need Expert Help? Hyperfix Your Elasticsearch Cluster
Stuck with ILM errors or EOL upgrades? Hyperflex delivers:
✅ Zero-Downtime Upgrades to Elasticsearch 7.x/8.x.
✅ ILM Policy Audits to prevent rollover failures.
✅ 24/7 Managed Elasticsearch for mission-critical clusters.