이 문서에서는 Linux 가상 머신(VM) 인스턴스에 루트 사용자로 연결하여 VM에 대한 수퍼유저 권한을 사용 설정하는 방법을 설명합니다. 기본적으로 공개 이미지로 빌드된 Compute Engine VM 및 대부분의 일반적인 운영체제에서는 SSH를 사용한 비밀번호가 포함된 루트 로그인을 허용하지 않습니다.
VM에 루트 사용자로 연결하는 대신 sudo를 통해 명령어를 실행할 수도 있습니다. 이 방법은 루트 로그인을 사용 설정하는 대신 사용하는 것이 좋습니다.
지원되는 운영체제
이러한 연결 방법은 Compute Engine에서 사용할 수 있는 모든 공개 Linux 이미지에 지원됩니다. Fedora CoreOS 이미지의 경우 이러한 방법을 사용하기 전에 SSH 액세스를 설정해야 합니다.
루트 로그인 사용 설정
기본적으로 Compute Engine VM에서는 /etc/ssh/sshd_config SSH 구성 파일에서 PermitRootLogin 매개변수를 prohibit-password 또는 no로 설정합니다. VM의 안내에 따라 루트 로그인을 사용 설정합니다.
At the bottom of the Google Cloud console, a
Cloud Shell
session starts and displays a command-line prompt. Cloud Shell is a shell environment
with the Google Cloud CLI
already installed and with values already set for
your current project. It can take a few seconds for the session to initialize.
[[["이해하기 쉬움","easyToUnderstand","thumb-up"],["문제가 해결됨","solvedMyProblem","thumb-up"],["기타","otherUp","thumb-up"]],[["이해하기 어려움","hardToUnderstand","thumb-down"],["잘못된 정보 또는 샘플 코드","incorrectInformationOrSampleCode","thumb-down"],["필요한 정보/샘플이 없음","missingTheInformationSamplesINeed","thumb-down"],["번역 문제","translationIssue","thumb-down"],["기타","otherDown","thumb-down"]],["최종 업데이트: 2025-07-26(UTC)"],[[["\u003cp\u003eThis document details how to enable and use root login for Linux virtual machines (VMs) on Compute Engine, although using \u003ccode\u003esudo\u003c/code\u003e is recommended as a more secure alternative.\u003c/p\u003e\n"],["\u003cp\u003eBy default, Compute Engine VMs prevent root login via password over SSH, requiring modifications to the \u003ccode\u003e/etc/ssh/sshd_config\u003c/code\u003e file, setting \u003ccode\u003ePermitRootLogin\u003c/code\u003e to \u003ccode\u003eprohibit-password\u003c/code\u003e, and creating and adding keys to the \u003ccode\u003eauthorized_keys\u003c/code\u003e file for root.\u003c/p\u003e\n"],["\u003cp\u003eThe process for enabling root login differs slightly between OS Login and Non-OS Login VMs, with OS Login VMs requiring the creation of an SSH key, while Non-OS Login VMs need to change SSH configuration settings.\u003c/p\u003e\n"],["\u003cp\u003eConnecting as the root user can be done via the \u003ccode\u003egcloud compute ssh\u003c/code\u003e command for VMs that do not have OS Login enabled, or through third-party tools for both OS Login and Non-OS Login VMs by using the root user key.\u003c/p\u003e\n"],["\u003cp\u003eTroubleshooting SSH connections and managing access and file transfers to VMs are also linked, and are relevant to the overall context of connecting to Linux VMs.\u003c/p\u003e\n"]]],[],null,["# Connect to Linux VMs as the root user\n\nLinux\n\n*** ** * ** ***\n\nThis document describes how to connect to Linux virtual machine (VM) instances\nas the root user, which enables superuser privileges on the VM. By default,\nCompute Engine VMs built from [public images](/compute/docs/images#os-details)\nand most common operating systems don't allow root login with a password over\nSSH.\n\nAn alternative to connecting to VMs as the root user is to run commands through\n`sudo`, which we recommend instead of enabling root login.\n\nSupported operating systems\n---------------------------\n\nThese connection methods are supported for all\n[public Linux images](/compute/docs/images/os-details) that are available on\nCompute Engine. For Fedora CoreOS images, you must\n[set up SSH access](https://docs.fedoraproject.org/en-US/fedora-coreos/tutorial-containers/)\nbefore you can use these methods.\n\nEnable root login\n-----------------\n\n| **Note:** We recommend running commands through `sudo` instead of enabling root login.\n\nBy default, Compute Engine VMs, set the `PermitRootLogin` parameter to\n`prohibit-password` or `no` in the `/etc/ssh/sshd_config` SSH configuration\nfile. Enable root login by following the instructions for your VM: \n\n### OS Login VMs\n\nEnable root login by doing the following:\n\n1. [Create an SSH key](/compute/docs/connect/create-ssh-keys). Copy the\n public SSH key for later.\n\n2. [Connect to the VM](/compute/docs/instances/connecting-to-instance) as\n you usually do.\n\n3. Change `PermitRootLogin no` to `PermitRootLogin prohibit-password` in the\n `/etc/ssh/sshd_config` file, by running the following command:\n\n ```\n sudo sed -i 's/PermitRootLogin no/PermitRootLogin prohibit-password/g' /etc/ssh/sshd_config\n ```\n4. Create the `/root/.ssh` directory using the following command:\n\n ```\n sudo mkdir /root/.ssh\n ```\n5. Set permissions on the `.ssh` directory, by running the following command:\n\n ```\n sudo chmod 700 /root/.ssh\n ```\n6. Create the `authorized_keys` file by running the following\n command:\n\n ```\n sudo touch /root/.ssh/authorized_keys\n ```\n7. Set permissions on the `authorized_keys` file, by running the following\n command:\n\n ```\n sudo chmod 600 /root/.ssh/authorized_keys\n ```\n8. Paste the public SSH key into the `/root/.ssh/authorized_keys` file.\n\n9. Restart the `sshd` daemon by restarting the VM, or running the restart\n command for your VM's operating system. Wait for the VM to reboot, then\n connect as the root user.\n\n### Non-OS Login VMs\n\nEnable root login by doing the following:\n\n1. [Connect to the VM](/compute/docs/instances/connecting-to-instance) as\n you usually do.\n\n2. Change `PermitRootLogin no` to `PermitRootLogin prohibit-password` in the\n `/etc/ssh/sshd_config` file, by running the following command:\n\n ```\n sudo sed -i 's/PermitRootLogin no/PermitRootLogin prohibit-password/g' /etc/ssh/sshd_config\n ```\n3. Restart the `sshd` daemon by restarting the VM, or running the restart\n command for your VM's operating system. Wait for the VM to reboot, then\n connect as the root user.\n\nConnect as the root user\n------------------------\n\nAfter you enable root login, connect to the VM as the root user. If\nyou're connecting to a VM that has OS Login enabled, you must use third-party\ntools instead of the gcloud CLI. \n\n### gcloud\n\n\nNote: You must use third-party tools to connect as the root user if the VM\nyou're connecting to has OS Login enabled.\n\nConnect to VMs as the root user by using the\n[`gcloud compute ssh` command](/sdk/gcloud/reference/compute/ssh) with\n`root@` specified before the VM name:\n\n1. In the Google Cloud console, activate Cloud Shell.\n\n [Activate Cloud Shell](https://console.cloud.google.com/?cloudshell=true)\n\n\n At the bottom of the Google Cloud console, a\n [Cloud Shell](/shell/docs/how-cloud-shell-works)\n session starts and displays a command-line prompt. Cloud Shell is a shell environment\n with the Google Cloud CLI\n already installed and with values already set for\n your current project. It can take a few seconds for the session to initialize.\n2. Connect to the VM by running the following command:\n\n ```\n gcloud compute ssh \\\n --project=PROJECT_ID \\\n --zone=ZONE \\\n root@VM_NAME\n ```\n\n Replace the following:\n - \u003cvar translate=\"no\"\u003ePROJECT_ID\u003c/var\u003e: the ID of the project that contains the VM\n - \u003cvar translate=\"no\"\u003eZONE\u003c/var\u003e: the name of the zone in which the VM is located\n - \u003cvar translate=\"no\"\u003eVM_NAME\u003c/var\u003e: the name of the VM\n\n### Third-party tools\n\n\nConnect to VMs as the root user by following the instructions for your VM:\n\n- **OS Login VMs**\n\n [Connect using third-party tools](/compute/docs/connect/ssh-using-third-party-tools)\n and specify the following:\n - **Private key** : the private key that corresponds with the public key that you added to the `authorized_keys` file\n - **Username** : the username must be `root`\n- **Non-OS Login VMs**\n\n 1. [Create an SSH key](/compute/docs/connect/create-ssh-keys) for the\n root user. The username for the key must be `root`.\n\n 2. [Add the key for the root user to metadata](/compute/docs/connect/add-ssh-keys#metadata).\n\n 3. [Connect using third-party tools](/compute/docs/connect/ssh-using-third-party-tools)\n and specify the following:\n\n - **Private key**: the private key for the root user\n\n - **Username** : the username must be `root`\n\nTroubleshooting\n---------------\n\nTo find methods for diagnosing and resolving failed SSH connections, see\n[Troubleshooting SSH](/compute/docs/troubleshooting/troubleshooting-ssh).\n\nWhat's next\n-----------\n\n- Learn how to [manage access to VMs](/compute/docs/instances/access-overview).\n- Learn how to [transfer files to VMs](/compute/docs/instances/transfer-files).\n- Learn how [SSH connections to Linux VMs](/compute/docs/instances/ssh) work on Compute Engine."]]
