Frequently Asked Questions

My rule is not getting any hits?

So you’ve managed to set up ElastAlert 2, write a rule, and run it, but nothing happens, or it says 0 query hits. First of all, we recommend using the command elastalert-test-rule rule.yaml to debug. It will show you how many documents match your filters for the last 24 hours (or more, see --help), and then shows you if any alerts would have fired. If you have a filter in your rule, remove it and try again. This will show you if the index is correct and that you have at least some documents. If you have a filter in Kibana and want to recreate it in ElastAlert 2, you probably want to use a query string. Your filter will look like

filter:
- query:
    query_string:
      query: "foo: bar AND baz: abc*"

If you receive an error that Elasticsearch is unable to parse it, it’s likely the YAML is not spaced correctly, and the filter is not in the right format. If you are using other types of filters, like term, a common pitfall is not realizing that you may need to use the analyzed token. This is the default if you are using Logstash. For example,

filter:
- term:
    foo: "Test Document"

will not match even if the original value for foo was exactly “Test Document”. Instead, you want to use foo.raw. If you are still having trouble troubleshooting why your documents do not match, try running ElastAlert 2 with --es_debug_trace /path/to/file.log. This will log the queries made to Elasticsearch in full so that you can see exactly what is happening.

I got hits, why didn’t I get an alert?

If you got logs that had X query hits, 0 matches, 0 alerts sent, it depends on the type why you didn’t get any alerts. If type: any, a match will occur for every hit. If you are using type: frequency, num_events must occur within timeframe of each other for a match to occur. Different rules apply for different rule types.

If you see X matches, 0 alerts sent, this may occur for several reasons. If you set aggregation, the alert will not be sent until after that time has elapsed. If you have gotten an alert for this same rule before, that rule may be silenced for a period of time. The default is one minute between alerts. If a rule is silenced, you will see Ignoring match for silenced rule in the logs.

If you see X alerts sent but didn’t get any alert, it’s probably related to the alert configuration. If you are using the --debug flag, you will not receive any alerts. Instead, the alert text will be written to the console. Use --verbose to achieve the same affects without preventing alerts. If you are using email alert, make sure you have it configured for an SMTP server. By default, it will connect to localhost on port 25. It will also use the word “elastalert” as the “From:” address. Some SMTP servers will reject this because it does not have a domain while others will add their own domain automatically. See the email section in the documentation for how to configure this.

Why did I only get one alert when I expected to get several?

There is a setting called realert which is the minimum time between two alerts for the same rule. Any alert that occurs within this time will simply be dropped. The default value for this is one minute. If you want to receive an alert for every single match, even if they occur right after each other, use

realert:
  minutes: 0

You can of course set it higher as well.

How can I prevent duplicate alerts?

By setting realert, you will prevent the same rule from alerting twice in an amount of time.

realert:
  days: 1

You can also prevent duplicates based on a certain field by using query_key. For example, to prevent multiple alerts for the same user, you might use

realert:
  hours: 8
query_key: user

Note that this will also affect the way many rule types work. If you are using type: frequency for example, num_events for a single value of query_key must occur before an alert will be sent. You can also use a compound of multiple fields for this key. For example, if you only wanted to receieve an alert once for a specific error and hostname, you could use

query_key: [error, hostname]

You can also write in the following way.

query_key:
  - error
  - hostname

Internally, this works by creating a new field for each document called field1,field2 with a value of value1,value2 and using that as the query_key.

The data for when an alert will fire again is stored in Elasticsearch in the elastalert_status index, with a _type\ ``ofsilence`` and also cached in memory.

How can I change what’s in the alert?

You can use the field alert_text to add custom text to an alert. By setting alert_text_type: alert_text_only Or alert_text_type: alert_text_jinja, it will be the entirety of the alert. You can also add different fields from the alert:

With alert_text_type: alert_text_jinja by using Jinja2 Template.

alert_text_type: alert_text_jinja

alert_text: |
  Alert triggered! *({{num_hits}} Matches!)*
  Something happened with {{username}} ({{email}})
  {{description|truncate}}
  • Top fields are accessible via {{field_name}} or {{_data['field_name']}}, _data is useful when accessing fields with dots in their keys, as Jinja treat dot as a nested field.

  • If _data conflicts with your top level data, use jinja_root_name to change its name.

With alert_text_type: alert_text_only by using Python style string formatting and alert_text_args. For example

alert_text: "Something happened with {0} at {1}"
alert_text_type: alert_text_only
alert_text_args: ["username", "@timestamp"]

You can also limit the alert to only containing certain fields from the document by using include.

include: ["ip_address", "hostname", "status"]

My alert only contains data for one event, how can I see more?

If you are using type: frequency, you can set the option attach_related: true and every document will be included in the alert. An alternative, which works for every type, is top_count_keys. This will show the top counts for each value for certain fields. For example, if you have

top_count_keys: ["ip_address", "status"]

and 10 documents matched your alert, it may contain something like

ip_address:
127.0.0.1: 7
10.0.0.1: 2
192.168.0.1: 1

status:
200: 9
500: 1

How can I make the alert come at a certain time?

The aggregation feature will take every alert that has occured over a period of time and send them together in one alert. You can use cron style syntax to send all alerts that have occured since the last once by using

aggregation:
  schedule: '2 4 * * mon,fri'

I have lots of documents and it’s really slow, how can I speed it up?

There are several ways to potentially speed up queries. If you are using index: logstash-*, Elasticsearch will query all shards, even if they do not possibly contain data with the correct timestamp. Instead, you can use Python time format strings and set use_strftime_index

index: logstash-%Y.%m
use_strftime_index: true

Another thing you could change is buffer_time. By default, ElastAlert 2 will query large overlapping windows in order to ensure that it does not miss any events, even if they are indexed in real time. In config.yaml, you can adjust buffer_time to a smaller number to only query the most recent few minutes.

buffer_time:
  minutes: 5

By default, ElastAlert 2 will download every document in full before processing them. Instead, you can have ElastAlert 2 simply get a count of the number of documents that have occured in between each query. To do this, set use_count_query: true. This cannot be used if you use query_key, because ElastAlert 2 will not know the contents of each documents, just the total number of them. This also reduces the precision of alerts, because all events that occur between each query will be rounded to a single timestamp.

If you are using query_key (a single key, not multiple keys) you can use use_terms_query. This will make ElastAlert 2 perform a terms aggregation to get the counts for each value of a certain field. May not be compatible with all rule types.

Can I perform aggregations?

The only aggregation supported currently is a terms aggregation, by setting use_terms_query.

I’m not using @timestamp, what do I do?

You can use timestamp_field to change which field ElastAlert 2 will use as the timestamp. You can use timestamp_type to change it between ISO 8601 and unix timestamps. You must have some kind of timestamp for ElastAlert 2 to work. If your events are not in real time, you can use query_delay and buffer_time to adjust when ElastAlert 2 will look for documents.

I’m using flatline but I don’t see any alerts

When using type: flatline, ElastAlert 2 must see at least one document before it will alert you that it has stopped seeing them.

How can I get a “resolve” event?

ElastAlert 2 does not currently support stateful alerts or resolve events. However, if you have a rule alerting you that a condition has occurred, such as a service being down, then you can create a second rule that will monitor the first rule, and alert you when the first rule ceases to trigger.

For example, assuming you already have a rule named “Service is offline” that’s working today, you can add a second rule as follows:

name: Service is back online
type: flatline
index: elastalert*
query_key: "rule_name"
filter:
- query:
    query_string:
      query: "rule_name:\"Service is offline\" AND matches:>0"
forget_keys: true
timeframe:
  minutes: 30
threshold: 1

This second rule will trigger after the timeframe of 30 minutes has elapsed with no further matches against the first rule.

Can I set a warning threshold?

Currently, the only way to set a warning threshold is by creating a second rule with a lower threshold.

Does it support Elastic Cloud’s “Cloud ID”?

While Elastic Cloud is supported via the traditional URL connection method, connecting via Cloud ID is not currently supported.

I need to go through an http (s) proxy to connect to Elasticsearch. Does ElastAlert 2 support it?

Not supported.

About boolean value

You can use all lowercase letters or only uppercase letters at the beginning.

example

# OK
use_ssl: true
# OK
use_ssl: True
# OK
use_ssl: false
# OK
use_ssl: False

Is it possible to send an SNMP Trap with an alert notification?

  • You need to additionally install snmp snmptrapd on the docker image. In other words, you need to modify the Dockerfile and recreate the Docker image with docker build.

  • It is possible with the command Alerter.

example

name: "mariadb-error-log-warning"
type: "frequency"
index: "mariadb-*"
num_events: 1
timeframe:
    minutes: 5
realert:
  minutes: 1
filter:
  - query:
      query_string:
        query: "@log_name:mysqld.error AND message:Warning"
alert:
  - command
command: ["/usr/bin/snmptrap", "-IR", "-v", "2c", "-c", "public", "xxx.xxx.xxx.xxxxx:xxx", "", "netSnmp.99999", "netSnmp.99999.1", "s", "Hello, World"]
is_enabled: true
timestamp_field: "@timestamp"
timestamp_type: "iso"
use_strftime_index: false

Is Email Alerter compatible with Microsoft 365 (formerly Office 365)?

Not supported.

Does Email Alerter support the Google Gmail API?

Not supported.

Can Email Alerter send emails via the Gmail sending server?

It is possible. However, you need to turn on (enable) the item “Access to insecure apps” in the “Security” settings of your Google account.

Is it possible to send a JPEG image encoded as base64 in elasticsearch as an image attachment with an Email Alerter?

Yes, this is possible if the base64 encoded bytes are available in the matched document, as shown in the example below:

include: [base64field]
alert_text_args: [base64field]
email_format: "html"
alert_text_type: alert_text_only
alert_text: |
  <html>
  <body>
  <div>
    <img src="data:image/jpg;base64, {}" alt="Image" />
  </div>
  </body>
  </html>

Does the alert notification destination support Alertmanager?

Now supported as of ElastAlert 2.2.3.

The es_host parameter seems to use only one host. Is it possible to specify multiple nodes?

There are two options:

  1. Use haproxy in front of elasticsearch to support multiple hosts.

  2. Use the new es_hosts parameter introduced in ElastAlert 2.2.3. See Configuration.

Is there any plan to implement a REST API into this project?

No plan.

An error occurred when trying to create a blacklist rule that parses a file with more than 1024 lines.

This is the default limit for ElasticSearch. Specifying more than 1024 items in the blacklist will result in an error. This is a known issue. Perhaps White List can have similar issues. See the following issues on the original yelp/elastalert for more information.

https://github.com/Yelp/elastalert/issues/1867
https://github.com/Yelp/elastalert/issues/2704

ElastAlert 2 doesn’t have a listening port?

ElastAlert 2 does not have a network API. There is no listening port. You can monitor its activity by viewing the console output or Docker logs.

I’ve set ssl_show_warn but it doesn’t seem to work.

Now supported as of ElastAlert 2.4.0.

How to write a query filter for phrases containing spaces?

To search for values containing spaces, or other special characters you will need to use escape characters. This is briefly mentioned at the bottom of the Lucene Query Parser Syntax documentation but does not go into extensive detail. Below are some examples to use in ElastAlert 2 rule filters.

Example 1 - Escaping double quotes within double quotes. Useful for embedded single quotes and double quotes in your search phrase:

filter:
 - query:
     query_string:
       query: "\"Women's Clothing\""

Example 2 - Avoiding escaping altogether by enclosing double quotes within single quotes:

filter:
 - query:
     query_string:
       query: '"Rabbia Al"'

Does ElastAlert 2 support Elasticsearch 8?

ElastAlert 2 supports Elasticsearch 8.

To upgrade an existing ElastAlert 2 installation to Elasticsearch 8 the following manual steps are required (note the important WARNING below):

  • Shutdown ElastAlert 2.

  • Delete the old elastalert* indices. See Elasticsearch documentation for instructions on how to delete via the API, or use the Kibana Index Management interface.

  • Upgrade the Elastic cluster to Elasticsearch 8 following the Elastic 8 upgrade instructions.

  • If NOT running ElastAlert 2 via Docker or Kubernetes, run elastalert-create-index to create the new indices. This is not needed when running via a container since the container always attempts to creates the indices at startup, if they’re not yet created.

  • Restart ElastAlert 2.

WARNING: Failure to remove the old ElastAlert indices can result in a non-working Elasticsearch cluster. This is because the ElastAlert indices contain deprecated features and the Elasticsearch 8 upgrade logic is currently flawed and does not correctly handle this situation. The Elasticsearch GitHub repository contains more information on this problem.

Support multiple sns_topic_arn in Alert Amazon SNS(Simple Notification Service)?

example

alert:
 - sns:
      sns_topic_arn: "aws-topic1"
 - sns:
      sns_topic_arn: "aws-topic2"

Support multiple telegram_room_id in Alert Telegram?

example

alert:
 - telegram:
      telegram_room_id: "AAA"
 - telegram:
      telegram_room_id: "BBB"
telegram_bot_token: "XXX"