Synthetics runtime versions - Amazon CloudWatch
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Synthetics runtime versions

When you create or update a canary, you choose a Synthetics runtime version for the canary. A Synthetics runtime is a combination of the Synthetics code that calls your script handler, and the Lambda layers of bundled dependencies.

CloudWatch Synthetics currently supports runtimes that use Node.js for scripts and the Puppeteer framework, and runtimes that use Python for scripting and Selenium Webdriver for the framework.

We recommend that you always use the most recent runtime version for your canaries, to be able to use the latest features and updates made to the Synthetics library.


Whenever you upgrade a canary to use a new version of the the Synthetics runtime, all Synthetics library functions that your canary uses are also automatically upgraded to the same version of NodeJS that the Synthetics runtime supports.

CloudWatch Synthetics runtime support policy

Synthetics runtime versions are subject to maintenance and security updates. When any component of a runtime version is no longer supported, that Synthetics runtime version is deprecated.

You can't create canaries using deprecated runtime versions. Canaries that use deprecated runtimes continue to run. You can stop, start, and delete these canaries. You can update an existing canary that uses a deprecated runtime version by updating the canary to use a supported runtime version.

CloudWatch Synthetics notifies you by email if you have canaries that use runtimes that are scheduled to be deprecated in the next 60 days. We recommend that you migrate your canaries to a supported runtime version to benefit from the new functionality, security, and performance enhancements that are included in more recent releases.

How do I update a canary to a new runtime version?

You can update a canary’s runtime version by using the CloudWatch console, Amazon CloudFormation, the Amazon CLI or the Amazon SDK. When you use the CloudWatch console, you can update up to five canaries at once by selecting them in the canary list page and then choosing Actions, Update Runtime.

You can verify the upgrade by first cloning the canary using the CloudWatch console and updating its runtime version. This creates another canary which is a clone of your original canary. Once you have verified your canary with the new runtime version, you can update the runtime version of your original canary and delete the clone canary.

You can also update multiple canaries using an upgrade script. For more information, see Canary runtime upgrade script.

If you upgrade a canary and it fails, see Troubleshooting a failed canary.

Runtime deprecation dates

Runtime Version Deprecation date


November 13, 2022


November 13, 2022


November 13, 2022


November 13, 2022


November 13, 2022


May 28, 2021


May 28, 2021


May 28, 2021


February 8, 2021


May 28, 2021

Canary runtime upgrade script

To upgrade a canary script to a supported runtime version, use the following script.

const AWS = require('aws-sdk'); // You need to configure your Amazon credentials and Region. // // const synthetics = new AWS.Synthetics(); const DEFAULT_OPTIONS = { /** * The number of canaries to upgrade during a single run of this script. */ count: 10, /** * No canaries are upgraded unless force is specified. */ force: false }; /** * The number of milliseconds to sleep between GetCanary calls when * verifying that an update succeeded. */ const SLEEP_TIME = 5000; (async () => { try { const options = getOptions(); const versions = await getRuntimeVersions(); const canaries = await getAllCanaries(); const upgrades = canaries .filter(canary => !versions.isLatestVersion(canary.RuntimeVersion)) .map(canary => { return { Name: canary.Name, FromVersion: canary.RuntimeVersion, ToVersion: versions.getLatestVersion(canary.RuntimeVersion) }; }); if (options.force) { const promises = []; for (const upgrade of upgrades.slice(0, options.count)) { const promise = upgradeCanary(upgrade); promises.push(promise); // Sleep for 100 milliseconds to avoid throttling. await usleep(100); } const succeeded = []; const failed = []; for (let i = 0; i < upgrades.slice(0, options.count).length; i++) { const upgrade = upgrades[i]; const promise = promises[i]; try { await promise; console.log(`The update of ${upgrade.Name} succeeded.`); succeeded.push(upgrade.Name); } catch (e) { console.log(`The update of ${upgrade.Name} failed with error: ${e}`); failed.push({ Name: upgrade.Name, Reason: e }); } } if (succeeded.length) {'The following canaries were upgraded successfully.'); for (const name of succeeded) { console.log(name); } console.groupEnd() } else { console.log('No canaries were upgraded successfully.'); } if (failed.length) {'The following canaries were not upgraded successfully.'); for (const failure of failed) { console.log('\x1b[31m', `${failure.Name}: ${failure.Reason}`, '\x1b[0m'); } console.groupEnd(); } } else { console.log('Run with --force [--count <count>] to perform the first <count> upgrades shown. The default value of <count> is 10.') console.table(upgrades); } } catch (e) { console.error(e); } })(); function getOptions() { const force = getFlag('--force', DEFAULT_OPTIONS.force); const count = getOption('--count', DEFAULT_OPTIONS.count); return { force, count }; function getFlag(key, defaultValue) { return process.argv.includes(key) || defaultValue; } function getOption(key, defaultValue) { const index = process.argv.indexOf(key); if (index < 0) { return defaultValue; } const value = process.argv[index + 1]; if (typeof value === 'undefined' || value.startsWith('-')) { throw `The ${key} option requires a value.`; } return value; } } function getAllCanaries() { return new Promise((resolve, reject) => { const canaries = []; synthetics.describeCanaries().eachPage((err, data) => { if (err) { reject(err); } else { if (data === null) { resolve(canaries); } else { canaries.push(; } } }); }); } function getRuntimeVersions() { return new Promise((resolve, reject) => { const jsVersions = []; const pythonVersions = []; synthetics.describeRuntimeVersions().eachPage((err, data) => { if (err) { reject(err); } else { if (data === null) { jsVersions.sort((a, b) => a.ReleaseDate - b.ReleaseDate); pythonVersions.sort((a, b) => a.ReleaseDate - b.ReleaseDate); resolve({ isLatestVersion(version) { const latest = this.getLatestVersion(version); return latest === version; }, getLatestVersion(version) { if (jsVersions.some(v => v.VersionName === version)) { return jsVersions[jsVersions.length - 1].VersionName; } else if (pythonVersions.some(v => v.VersionName === version)) { return pythonVersions[pythonVersions.length - 1].VersionName; } else { throw Error(`Unknown version ${version}`); } } }); } else { for (const version of data.RuntimeVersions) { if (version.VersionName === 'syn-1.0') { jsVersions.push(version); } else if (version.VersionName.startsWith('syn-nodejs-2.')) { jsVersions.push(version); } else if (version.VersionName.startsWith('syn-nodejs-puppeteer-')) { jsVersions.push(version); } else if (version.VersionName.startsWith('syn-python-selenium-')) { pythonVersions.push(version); } else { throw Error(`Unknown version ${version.VersionName}`); } } } } }); }); } async function upgradeCanary(upgrade) { console.log(`Upgrading canary ${upgrade.Name} from ${upgrade.FromVersion} to ${upgrade.ToVersion}`); await synthetics.updateCanary({ Name: upgrade.Name, RuntimeVersion: upgrade.ToVersion }).promise(); while (true) { await usleep(SLEEP_TIME); console.log(`Getting the state of canary ${upgrade.Name}`); const response = await synthetics.getCanary({ Name: upgrade.Name }).promise(); const state = response.Canary.Status.State; console.log(`The state of canary ${upgrade.Name} is ${state}`); if (state === 'ERROR' || response.Canary.Status.StateReason) { throw response.Canary.Status.StateReason; } if (state !== 'UPDATING') { return; } } } function usleep(ms) { return new Promise(resolve => setTimeout(resolve, ms)); }