Specifies the starting byte position of the output to return. To start with the first byte of output to the specified port, omit this field or set it to 0.
If the output for that byte position is available, this field matches the start parameter sent with the request. If the amount of serial console output exceeds the size of the buffer (1 MB), the oldest output is discarded and is no longer available. If the requested start position refers to discarded output, the start position is adjusted to the oldest output still available, and the adjusted start position is returned as the start property value.
You can also provide a negative start position, which translates to the most recent number of bytes written to the serial port. For example, -3 is interpreted as the most recent 3 bytes written to the serial console. Note that the negative start is bounded by the retained buffer size, and the returned serial console output will not exceed the max buffer size.
Request body
The request body must be empty.
Response body
An instance serial console output.
If successful, the response body contains data with the following structure:
The starting byte position of the output that was returned. This should match the start parameter sent with the request. If the serial console output exceeds the size of the buffer (1 MB), older output is overwritten by newer content. The output start value will indicate the byte position of the output that was returned, which might be different than the start value that was specified in the request.
[Output Only] The position of the next byte of content, regardless of whether the content exists, following the output returned in the contents property. Use this value in the next request as the start parameter.
selfLink
string
[Output Only] Server-defined URL for this resource.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-03-11 UTC."],[[["This document outlines how to retrieve the last 1 MB of serial port output from a specified Compute Engine instance using an HTTP GET request."],["The HTTP request requires the project ID, zone, and instance name as path parameters, and it can accept optional query parameters such as `port` and `start` to specify the COM port and starting byte position."],["The request body must be empty, and the response body will contain the serial console output, which is formatted as a JSON object with fields like `kind`, `contents`, `start`, `next`, and `selfLink`."],["Retrieving serial port data requires one of the specified OAuth scopes or the `compute.instances.getSerialPortOutput` IAM permission."],["The `start` query parameter can be set to negative values to get the most recent bytes, but it is bounded by the retained buffer size of the serial port."]]],[]]
