Riduci la latenza utilizzando le policy di posizionamento compatto
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Questo documento spiega come ridurre la latenza di rete tra le VM di un job specificando una policy di posizionamento compatto.
Se gli host VM sono fisicamente più vicini tra loro all'interno di una
zona, è possibile ridurre la latenza di rete tra le VM. Questo vantaggio in termini di prestazioni può essere particolarmente utile
per i job con attività strettamente accoppiate, ad esempio
attività che comunicano utilizzando le librerie MPI.
Quando crei un job, puoi richiedere facoltativamente che le VM di un job si trovino più vicine tra loro specificando una policy di posizionamento compatto.
In caso contrario, il posizionamento predefinito delle VM in genere distribuisce le VM su host separati per ridurre al minimo l'impatto delle interruzioni di corrente.
Quando specifichi che un job deve utilizzare una policy di posizionamento compatto, Batch crea ed elimina automaticamente una policy di posizionamento compatto per le VM del job. Non puoi specificare una policy di posizionamento compatto esistente per un job.
Non puoi specificare un numero di VM per la policy di posizionamento compatto.
La policy di posizionamento compatto per un job si applica indipendentemente dal numero di VM su cui viene eseguito il job.
Crea ed esegui un job che utilizza una policy di posizionamento
Puoi specificare che un job utilizzi una policy di posizionamento compatto impostando il
campo collocation su COLLOCATED utilizzando gcloud CLI o l'API Batch.
gcloud
Crea un file JSON che specifichi i dettagli di configurazione del job e imposti
il campo collocation su COLLOCATED.
Ad esempio, per creare un job di script di base che specifica una
policy di posizionamento compatto, crea un file JSON con i seguenti contenuti:
{"taskGroups":[{"taskSpec":{"runnables":[{"script":{"text":"echo Hello world from task ${BATCH_TASK_INDEX}"}}]},"taskCount":3}],"allocationPolicy":{"placement":{"collocation":"COLLOCATED"}},"logsPolicy":{"destination":"CLOUD_LOGGING"}}
JSON_CONFIGURATION_FILE: il percorso di un file JSON con i dettagli di configurazione del job.
API
Effettua una richiesta POST al
metodo jobs.create
che imposta il campo collocation su COLLOCATED.
Ad esempio, per creare un job di script di base che specifichi una
policy di posizionamento compatto, effettua la seguente richiesta:
POSThttps://batch.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/jobs?job_id=JOB_NAME{"taskGroups":[{"taskSpec":{"runnables":[{"script":{"text":"echo Hello world from task ${BATCH_TASK_INDEX}"}}]},"taskCount":3}],"allocationPolicy":{"placement":{"collocation":"COLLOCATED"}},"logsPolicy":{"destination":"CLOUD_LOGGING"}}
[[["Facile da capire","easyToUnderstand","thumb-up"],["Il problema è stato risolto","solvedMyProblem","thumb-up"],["Altra","otherUp","thumb-up"]],[["Difficile da capire","hardToUnderstand","thumb-down"],["Informazioni o codice di esempio errati","incorrectInformationOrSampleCode","thumb-down"],["Mancano le informazioni o gli esempi di cui ho bisogno","missingTheInformationSamplesINeed","thumb-down"],["Problema di traduzione","translationIssue","thumb-down"],["Altra","otherDown","thumb-down"]],["Ultimo aggiornamento 2025-09-05 UTC."],[[["\u003cp\u003eSpecifying a compact placement policy reduces network latency between a job's virtual machines (VMs) by ensuring they are located on physically closer hosts within a zone.\u003c/p\u003e\n"],["\u003cp\u003eCompact placement policies are beneficial for jobs with tightly coupled tasks, especially those that utilize MPI libraries for communication.\u003c/p\u003e\n"],["\u003cp\u003eBatch automatically creates and manages compact placement policies when specified, without the ability to use a pre-existing one or specifying the number of VMs.\u003c/p\u003e\n"],["\u003cp\u003eYou can set a compact placement policy for a job by setting the \u003ccode\u003ecollocation\u003c/code\u003e field to \u003ccode\u003eCOLLOCATED\u003c/code\u003e in the job configuration, either through the gcloud CLI or the Batch API.\u003c/p\u003e\n"],["\u003cp\u003eBefore creating a job, ensure you have the necessary permissions, which includes the Batch Job Editor role and the Service Account User role.\u003c/p\u003e\n"]]],[],null,["# Reduce latency by using compact placement policies\n\nThis document explains how to reduce network latency among a job's VMs by\nspecifying a compact placement policy.\n\nHaving VM hosts that are physically closer to each other within a\n[zone](/compute/docs/regions-zones#zones_and_clusters) can reduce\nnetwork latency between VMs. This performance benefit can be especially useful\nfor jobs with tightly coupled tasks, such as\n[tasks that communicate using MPI libraries](/batch/docs/create-run-job-mpi-library).\nWhen you create a job, you can optionally require a job's VMs to be located\ncloser to each other by specifying a compact placement policy.\nOtherwise, default VM placement typically distributes VMs across\nseparate hosts to help minimize the impact of power failures.\n\nTo learn more about compact placement policies, see\n[About placement policies](/compute/docs/instances/placement-policies-overview)\nin the Compute Engine documentation.\n\nBefore you begin\n----------------\n\n1. If you haven't used Batch before, review [Get started with Batch](/batch/docs/get-started) and enable Batch by completing the [prerequisites for projects and users](/batch/docs/get-started#prerequisites).\n2.\n\n To get the permissions that\n you need to create a job,\n\n ask your administrator to grant you the\n following IAM roles:\n\n - [Batch Job Editor](/iam/docs/roles-permissions/batch#batch.jobsEditor) (`roles/batch.jobsEditor`) on the project\n - [Service Account User](/iam/docs/roles-permissions/iam#iam.serviceAccountUser) (`roles/iam.serviceAccountUser`) on the [job's service account](/batch/docs/create-run-job-custom-service-account#create-job-service-account), which by default is the [default Compute Engine service account](/compute/docs/access/service-accounts#default_service_account)\n\n\n For more information about granting roles, see [Manage access to projects, folders, and organizations](/iam/docs/granting-changing-revoking-access).\n\n\n You might also be able to get\n the required permissions through [custom\n roles](/iam/docs/creating-custom-roles) or other [predefined\n roles](/iam/docs/roles-overview#predefined).\n\n\u003cbr /\u003e\n\nRestrictions\n------------\n\nIn addition to the\n[general restrictions for compact placement policies](/compute/docs/instances/placement-policies-overview#restrictions-compact-policies),\nBatch also has the following restrictions:\n\n- When you specify for a job to use a compact placement policy, Batch automatically creates and deletes a compact placement policy for the job's VMs. You can't specify an existing compact placement policy for a job.\n- You can't specify a number of VMs for the compact placement policy. The compact placement policy for a job applies regardless of how many VMs the job runs on.\n\nCreate and run a job that uses a placement policy\n-------------------------------------------------\n\nYou can specify for a job to use a compact placement policy by setting the\n[`collocation` field](/batch/docs/reference/rest/v1/projects.locations.jobs#PlacementPolicy.FIELDS.collocation)\nto `COLLOCATED` using the gcloud CLI or Batch API. \n\n### gcloud\n\n1. Create a JSON file that specifies the job's configuration details and sets\n the `collocation` field to `COLLOCATED`.\n\n For example, to create a basic script job that specifies a\n compact placement policy, create a JSON file with the following contents: \n\n {\n \"taskGroups\": [\n {\n \"taskSpec\": {\n \"runnables\": [\n {\n \"script\": {\n \"text\": \"echo Hello world from task ${BATCH_TASK_INDEX}\"\n }\n }\n ]\n },\n \"taskCount\": 3\n }\n ],\n \"allocationPolicy\": {\n \"placement\": {\n \"collocation\": \"COLLOCATED\"\n }\n },\n \"logsPolicy\": {\n \"destination\": \"CLOUD_LOGGING\"\n }\n }\n\n2. To create and run the job, use the\n [`gcloud batch jobs submit` command](/sdk/gcloud/reference/batch/jobs/submit):\n\n gcloud batch jobs submit \u003cvar translate=\"no\"\u003eJOB_NAME\u003c/var\u003e \\\n --location \u003cvar translate=\"no\"\u003eLOCATION\u003c/var\u003e \\\n --config \u003cvar translate=\"no\"\u003eJSON_CONFIGURATION_FILE\u003c/var\u003e\n\n Replace the following:\n - \u003cvar translate=\"no\"\u003eJOB_NAME\u003c/var\u003e: the name of the job.\n\n - \u003cvar translate=\"no\"\u003eLOCATION\u003c/var\u003e: the [location](/batch/docs/locations)\n of the job.\n\n - \u003cvar translate=\"no\"\u003eJSON_CONFIGURATION_FILE\u003c/var\u003e: the path for a JSON\n file with the job's configuration details.\n\n### API\n\nMake a `POST` request to the\n[`jobs.create` method](/batch/docs/reference/rest/v1/projects.locations.jobs/create)\nthat sets the `collocation` field to `COLLOCATED`.\n\nFor example, to create a basic script job that specifies a\ncompact placement policy, make the following request: \n\n POST https://batch.googleapis.com/v1/projects/\u003cvar translate=\"no\"\u003ePROJECT_ID\u003c/var\u003e/locations/\u003cvar translate=\"no\"\u003eLOCATION\u003c/var\u003e/jobs?job_id=\u003cvar translate=\"no\"\u003eJOB_NAME\u003c/var\u003e\n\n {\n \"taskGroups\": [\n {\n \"taskSpec\": {\n \"runnables\": [\n {\n \"script\": {\n \"text\": \"echo Hello world from task ${BATCH_TASK_INDEX}\"\n }\n }\n ]\n },\n \"taskCount\": 3\n }\n ],\n \"allocationPolicy\": {\n \"placement\": {\n \"collocation\": \"COLLOCATED\"\n }\n },\n \"logsPolicy\": {\n \"destination\": \"CLOUD_LOGGING\"\n }\n }\n\nReplace the following:\n\n- \u003cvar translate=\"no\"\u003ePROJECT_ID\u003c/var\u003e: the\n [project ID](/resource-manager/docs/creating-managing-projects#identifying_projects)\n of your project.\n\n- \u003cvar translate=\"no\"\u003eLOCATION\u003c/var\u003e: the [location](/batch/docs/locations)\n of the job.\n\n- \u003cvar translate=\"no\"\u003eJOB_NAME\u003c/var\u003e: the name of the job.\n\nWhat's next\n-----------\n\n- If you have issues creating or running a job, see [Troubleshooting](/batch/docs/troubleshooting).\n- [View jobs and tasks](/batch/docs/view-jobs-tasks).\n- Learn about more [job creation options](/batch/docs/create-run-job#job-creation-options)."]]