Terraform module for Datadog Sql Server

This module requires the sql server integration to be configured. It has basic SQL Server monitoring. Locks, process blocked, connectivity. It's best to also use Datadog's APM instrumentation to understand the way the application is using the database. There's an upcoming feature in Datadog to fully support deep dive database monitoring.

This module is part of a larger suite of modules that provide alerts in Datadog. Other modules can be found on the Terraform Registry

We have two base modules we use to standardise development of our Monitor Modules:

• generic monitor Used in 90% of our alerts
• service check monitor

Modules are generated with this tool: https://github.com/kabisa/datadog-terraform-generator

Example Usage

module "sql_server" {
  source = "kabisa/sql-server/datadog"

  notification_channel       = "@mail@example.com"
  service                    = "SQL Server"
  env                        = "prd"
  filter_str                 = "role:sqlserver"
  service_check_include_tags = ["role:sqlserver"]
}

Module Variables

Monitors:

Monitor name	Default enabled	Priority	Query
Batches Compiled Percent	True	4	avg(last_1d):(max:sqlserver.stats.sql_compilations{tag:xxx} by {host} / max:sqlserver.stats.batch_requests{tag:xxx} by {host}) * 100 >= 20
Buffer Cache Hit Ratio	True	4	avg(last_1d):min:sqlserver.buffer.cache_hit_ratio{tag:xxx} by {host} * 100 < 75
Connections	True	3	avg(last_30m):max:sqlserver.stats.connections{tag:xxx} by {host} >= 500
Database State	True	1	max(last_5m):max:sqlserver.database.state{tag:xxx} by {host,database,database_state_desc} >= 5
Lock Waits	True	4	avg(last_30m):max:sqlserver.stats.lock_waits{tag:xxx} by {host} > 20
Page Life Expectancy	True	4	avg(last_1d):min:sqlserver.buffer.page_life_expectancy{tag:xxx} by {host} < 900
Procs Blocked	True	3	avg(last_10m):max:sqlserver.stats.procs_blocked{tag:xxx} by {host} >= 1

Getting started developing

pre-commit was used to do Terraform linting and validating.

Steps:

• Install pre-commit. E.g. brew install pre-commit.
• Run pre-commit install in this repo. (Every time you clone a repo with pre-commit enabled you will need to run the pre-commit install command)
• That’s it! Now every time you commit a code change (.tf file), the hooks in the hooks: config .pre-commit-config.yaml will execute.

Batches Compiled Percent

When this metric is high, a lot of queries need to be recompiled. Consider parameterizing more queries by using stored procedures, using forced parameterization or allocating more memory.

Query:

avg(last_1d):(max:sqlserver.stats.sql_compilations{tag:xxx} by {host} / max:sqlserver.stats.batch_requests{tag:xxx} by {host}) * 100 >= 20

variable	default	required	description
batches_compiled_percent_enabled	True	No
batches_compiled_percent_warning	10	No
batches_compiled_percent_critical	20	No
batches_compiled_percent_evaluation_period	last_1d	No
batches_compiled_percent_note	""	No
batches_compiled_percent_docs	When this metric is high, a lot of queries need to be recompiled. Consider parameterizing more queries by using stored procedures, using forced parameterization or allocating more memory.	No
batches_compiled_percent_filter_override	""	No
batches_compiled_percent_alerting_enabled	True	No
batches_compiled_percent_priority	4	No	Number from 1 (high) to 5 (low).

Buffer Cache Hit Ratio

When this metric is low, pages are often read from disk. Consider allocating more memory.

Query:

avg(last_1d):min:sqlserver.buffer.cache_hit_ratio{tag:xxx} by {host} * 100 < 75

variable	default	required	description
buffer_cache_hit_ratio_enabled	True	No
buffer_cache_hit_ratio_warning	90	No
buffer_cache_hit_ratio_critical	75	No
buffer_cache_hit_ratio_evaluation_period	last_1d	No
buffer_cache_hit_ratio_note	""	No
buffer_cache_hit_ratio_docs	When this metric is low, pages are often read from disk. Consider allocating more memory.	No
buffer_cache_hit_ratio_filter_override	""	No
buffer_cache_hit_ratio_alerting_enabled	True	No
buffer_cache_hit_ratio_priority	4	No	Number from 1 (high) to 5 (low).

Can Connect

variable	default	required	description
can_connect_enabled	True	No
can_connect_alerting_enabled	True	No
can_connect_warning	1	No
can_connect_critical	1	No
can_connect_priority	1	No
can_connect_docs	""	No
can_connect_note	""	No

Connections

Query:

avg(last_30m):max:sqlserver.stats.connections{tag:xxx} by {host} >= 500

variable	default	required	description
connections_enabled	True	No
connections_warning	400	No
connections_critical	500	No
connections_evaluation_period	last_30m	No
connections_note	""	No
connections_docs	""	No
connections_filter_override	""	No
connections_alerting_enabled	True	No
connections_priority	3	No	Number from 1 (high) to 5 (low).

Database State

Query:

max(last_5m):max:sqlserver.database.state{tag:xxx} by {host,database,database_state_desc} >= 5

variable	default	required	description
database_state_enabled	True	No
database_state_warning	1	No
database_state_critical	5	No
database_state_evaluation_period	last_5m	No
database_state_note	""	No
database_state_docs	""	No
database_state_filter_override	""	No
database_state_alerting_enabled	True	No
database_state_priority	1	No	Number from 1 (high) to 5 (low).

Lock Waits

High numbers of lock waits per second is caused by lock contention. Try reducing lock contention by using more fine grained locking in the queries.

Query:

avg(last_30m):max:sqlserver.stats.lock_waits{tag:xxx} by {host} > 20

variable	default	required	description
lock_waits_enabled	True	No
lock_waits_warning	10	No
lock_waits_critical	20	No
lock_waits_evaluation_period	last_30m	No
lock_waits_note	""	No
lock_waits_docs	High numbers of lock waits per second is caused by lock contention. Try reducing lock contention by using more fine grained locking in the queries.	No
lock_waits_filter_override	""	No
lock_waits_alerting_enabled	True	No
lock_waits_priority	4	No	Number from 1 (high) to 5 (low).

Page Life Expectancy

When this metric is low, pages are not being cached for a short time and often read from disk. Consider allocating more memory.

Query:

avg(last_1d):min:sqlserver.buffer.page_life_expectancy{tag:xxx} by {host} < 900

variable	default	required	description
page_life_expectancy_enabled	True	No
page_life_expectancy_warning	1800	No
page_life_expectancy_critical	900	No
page_life_expectancy_evaluation_period	last_1d	No
page_life_expectancy_note	""	No
page_life_expectancy_docs	When this metric is low, pages are not being cached for a short time and often read from disk. Consider allocating more memory.	No
page_life_expectancy_filter_override	""	No
page_life_expectancy_alerting_enabled	True	No
page_life_expectancy_priority	4	No	Number from 1 (high) to 5 (low).

Procs Blocked

High number of procs blocked can indicate deadlocks. Check for deadlocks by investigating which queries are waiting for locks to be released.

Query:

avg(last_10m):max:sqlserver.stats.procs_blocked{tag:xxx} by {host} >= 1

variable	default	required	description
procs_blocked_enabled	True	No
procs_blocked_warning	None	No
procs_blocked_critical	1	No
procs_blocked_evaluation_period	last_10m	No
procs_blocked_note	""	No
procs_blocked_docs	High number of procs blocked can indicate deadlocks. Check for deadlocks by investigating which queries are waiting for locks to be released.	No
procs_blocked_filter_override	""	No
procs_blocked_alerting_enabled	True	No
procs_blocked_priority	3	No	Number from 1 (high) to 5 (low).

Module Variables

variable	default	required	description
env		Yes
filter_str		Yes
service		Yes
notification_channel		Yes
additional_tags	[]	No
name_prefix	""	No
name_suffix	""	No
locked	True	No
service_check_include_tags	None	No
service_check_exclude_tags	None	No