http¶

Generate requests for an HTTP service and and collect latency and error-related metrics.

Usage example¶

In this experiment, the http task generates requests for https://httpbin.org/get, and collects latency and error-related metrics. The metrics are used by the assess task to validate SLOs.

Single endpoint:

iter8 k launch \
--set "tasks={http,assess}" \
--set http.url=https://httpbin.org/get \
--set assess.SLOs.upper.http/latency-mean=50 \
--set assess.SLOs.upper.http/error-count=0 \
--set runner=job

Multiple endpoints:

iter8 k launch \
--set "tasks={http,assess}" \
--set http.endpoints.get.url=http://httpbin.default/get \
--set http.endpoints.getAnything.url=http://httpbin.default/anything \
--set http.endpoints.post.url=http://httpbin.default/post \
--set http.endpoints.post.payloadStr=hello \
--set assess.SLOs.upper.http-get/error-count=0 \
--set assess.SLOs.upper.http-getAnything/error-count=0 \
--set assess.SLOs.upper.http-post/error-count=0 \
--set runner=job

Parameters¶

Name	Type	Description
url	string (URL)	URL where requests are sent.
headers	map[string]string	HTTP headers to use in the requests.
numRequests	int	Number of requests to be sent to the app. Default value is 100.
duration	string	Duration of this task. Specified in the Go duration string format (example, `5s`). If both duration and numRequests are specified, then duration is ignored.
qps	float	qps stands for queries-per-second. Number of requests per second sent to the app. Default value is 8.0.
connections	int	Number of parallel connections used to send requests. Default value is 4.
payloadURL	string (URL)	URL from which to download the content that will be used as the request payload. If this field is specified, Iter8 will send HTTP POST requests to the app using this content as the payload.
payloadStr	string	String data to be used as the request payload. If this field is specified, Iter8 will send HTTP POST requests to the app using this string as the payload.
contentType	string	Content type of the payload. This is intended to be used in conjunction with one of the `payload*` fields. If this field is specified, Iter8 will send HTTP POST requests to the app using this as the Content-Type header value.
warmupNumRequests	int	Number of requests to be sent in a warmup task (results are ignored).
warmupDuration	string	Duration of warmup task (results are ignored). Specified in the Go duration string format (example, 5s). If both warmupDuration and warmupNumRequests are specified, then warmupDuration is ignored.
endpoints	map[string]EndPoint	Used to specify multiple endpoints and their configuration. The `string` is the name of the endpoint and the `EndPoint` struct includes all the parameters described above. Load testing and metric collection will be conducted separately for each endpoint.

Precedence¶

Some parameters have a default value, which can be overwritten. In addition, with the endpoints parameter, you can test multiple endpoints and configure parameters for each of those endpoint. In these cases, the priority order is the default value, the value set at the base level, and the value set at the endpoint value.

In the following example, all three endpoints will use the default qps (queries-per-second) of 8.

iter8 k launch \
--set "tasks={http,assess}" \
--set http.endpoints.get.url=http://httpbin.default/get \
--set http.endpoints.getAnything.url=http://httpbin.default/anything \
--set http.endpoints.post.url=http://httpbin.default/post \
--set http.endpoints.post.payloadStr=hello \
--set assess.SLOs.upper.http-get/error-count=0 \
--set assess.SLOs.upper.http-getAnything/error-count=0 \
--set assess.SLOs.upper.http-post/error-count=0 \
--set runner=job

In the following example, the get and getAnything endpoints will use the default qps of 8 and the post endpoint will use a qps of 15.

iter8 k launch \
--set "tasks={http,assess}" \
--set http.endpoints.get.url=http://httpbin.default/get \
--set http.endpoints.getAnything.url=http://httpbin.default/anything \
--set http.endpoints.post.url=http://httpbin.default/post \
--set http.endpoints.post.payloadStr=hello \
--set http.endpoints.post.qps=15 \
--set assess.SLOs.upper.http-get/error-count=0 \
--set assess.SLOs.upper.http-getAnything/error-count=0 \
--set assess.SLOs.upper.http-post/error-count=0 \
--set runner=job

In the following example, all three endpoints will use a qps (queries-per-second) of 10.

iter8 k launch \
--set "tasks={http,assess}" \
--set http.qps=10 \
--set http.endpoints.get.url=http://httpbin.default/get \
--set http.endpoints.getAnything.url=http://httpbin.default/anything \
--set http.endpoints.post.url=http://httpbin.default/post \
--set http.endpoints.post.payloadStr=hello \
--set assess.SLOs.upper.http-get/error-count=0 \
--set assess.SLOs.upper.http-getAnything/error-count=0 \
--set assess.SLOs.upper.http-post/error-count=0 \
--set runner=job

In the following example, the get and getAnything endpoints will use a qps of 10 and the post endpoint will use a qps of 15.

iter8 k launch \
--set "tasks={http,assess}" \
--set http.qps=10 \
--set http.endpoints.get.url=http://httpbin.default/get \
--set http.endpoints.getAnything.url=http://httpbin.default/anything \
--set http.endpoints.post.url=http://httpbin.default/post \
--set http.endpoints.post.payloadStr=hello \
--set http.endpoints.post.qps=15 \
--set assess.SLOs.upper.http-get/error-count=0 \
--set assess.SLOs.upper.http-getAnything/error-count=0 \
--set assess.SLOs.upper.http-post/error-count=0 \
--set runner=job

Further more, set parameters will trickle down to the endpoints.

iter8 k launch \
--set "tasks={http,assess}" \
--set http.numRequests=50 \
--set http.endpoints.get.url=http://httpbin.default/get \
--set http.endpoints.getAnything.url=http://httpbin.default/anything \
--set http.endpoints.post.url=http://httpbin.default/post \
--set http.endpoints.post.payloadStr=hello \
--set assess.SLOs.upper.http-get/error-count=0 \
--set assess.SLOs.upper.http-getAnything/error-count=0 \
--set assess.SLOs.upper.http-post/error-count=0 \
--set runner=job

In this example, all three endpoints will have a numRequests of 50.

Metrics¶

This task creates a built-in provider named http. The following metrics are collected by this task:

http/request-count: total number of requests sent
http/error-count: number of error responses
http/error-rate: fraction of error responses
http/latency-mean: mean of observed latency values
http/latency-stddev: standard deviation of observed latency values
http/latency-min: min of observed latency values
http/latency-max: max of observed latency values
http/latency-pX: X^th percentile latency, for X in [50.0, 75.0, 90.0, 95.0, 99.0, 99.9]

All latency metrics have msec units.

In the case of multiple endpoints, the name of the endpoint will be appended to the name of the provider. For example, if the endpoint name is httpbin, then the following metrics would be collected by this task:

http-httpbin/request-count: total number of requests sent
http-httpbin/error-count: number of error responses
http-httpbin/error-rate: fraction of error responses
http-httpbin/latency-mean: mean of observed latency values
http-httpbin/latency-stddev: standard deviation of observed latency values
http-httpbin/latency-min: min of observed latency values
http-httpbin/latency-max: max of observed latency values
http-httpbin/latency-pX: X^th percentile latency, for X in [50.0, 75.0, 90.0, 95.0, 99.0, 99.9]

To learn more about the names of metrics, please see here.