snatch-instance: init

1 files changed, 354 insertions, 0 deletions

diff --git a/bin/snatch-instance b/bin/snatch-instance
new file mode 100755
index 0000000..f4f051c
--- /dev/null
+++ b/bin/snatch-instance
@@ -0,0 +1,354 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -i bash -p coreutils file gnugrep jq oci-cli openssh terraform
+#
+# usage: snatch-instance [PARAM...]
+#
+# Obtain a compute instance at OCI, and terminate once successful.
+# This program might be useful when Oracle is out of host capacity.
+#
+# For possible values of PARAM search for "Available parameters" in this file.
+
+set -efu
+
+main() {(
+
+  # Available parameters and their default values.
+  # Change parameters via command line using following syntax:
+  #   --NAME=VALUE
+  # where NAME is one of param_NAME below.
+  #
+  # Example: --display_name=mycomputer
+  param_apply=true
+  param_availability_domain_list_json=
+  param_display_name=computer
+  param_shape=VM.Standard.A1.Flex
+  param_memory_in_gbs=24
+  param_ocpus=4
+  param_ssh_authorized_key_file=$HOME/.ssh/id_rsa.pub
+  param_workdir=
+  param_compartment_id=
+  param_source_id=
+  param_subnet_id=
+
+  # Set parameters from command line.
+  for arg; do
+    case $arg in
+      --*=*)
+        readonly "param_${arg#--}"
+        ;;
+      *)
+        echo "$0: warning: ignoring unknown argument: $arg" >&2
+    esac
+  done
+
+  #
+  # Compute parameter defaults for each unset parameter.
+  #
+
+  if test -n "$param_apply"; then
+    conf_apply=$param_apply
+  else
+    echo "$0: error: undefined parameter: $param_apply" >&2
+    exit 2
+  fi
+  echo "$0: apply: $conf_apply" >&2
+
+  if test -n "$param_display_name"; then
+    conf_display_name=$param_display_name
+  else
+    echo "$0: error: undefined parameter: $param_display_name" >&2
+    exit 2
+  fi
+  echo "$0: display_name: $conf_display_name" >&2
+
+  if test -n "$param_ssh_authorized_key_file"; then
+    if ! is_ssh_public_key "$param_ssh_authorized_key_file"; then
+      echo "$0: error: not an ssh public key: $param_ssh_authorized_key_file" >&2
+      exit 1
+    fi
+    conf_ssh_authorized_key=$(cat "$param_ssh_authorized_key_file")
+  else
+    echo "$0: error: undefined parameter: $param_ssh_authorized_key_file" >&2
+    exit 2
+  fi
+
+  if test -n "$param_workdir"; then
+    conf_workdir=$param_workdir
+    mkdir -v -p "$conf_workdir"
+  else
+    conf_workdir=$(mktemp -d -t oci.snatch-instance.$$.XXXXXXXX)
+    trap cleanup EXIT
+    cleanup() {
+      rm -v -R "$conf_workdir"
+    }
+  fi
+  echo "$0: workdir: $conf_workdir" >&2
+
+  if test -n "$param_compartment_id"; then
+    conf_compartment_id=$param_compartment_id
+  else
+    conf_compartment_id=$(
+      export response="$(
+        oci iam compartment list \
+            --lifecycle-state=ACTIVE \
+      )"
+      jq -enr '
+        def assert(cond; msg): if cond then . else error(msg) end;
+
+        env.response | fromjson |
+        .data |
+        assert(length == 1; "could not find exactly one compartment") |
+        .[0] |
+        .["compartment-id"]
+      '
+    )
+  fi
+  echo "$0: compartment_id: $conf_compartment_id" >&2
+
+  if test -n "$param_availability_domain_list_json"; then
+    conf_availability_domain_list_json=$param_availability_domain_list_json
+  else
+    conf_availability_domain_list_json=$(
+      export response="$(
+        oci iam availability-domain list \
+            --compartment-id="$conf_compartment_id"
+      )"
+      jq -enr '
+        env.response | fromjson |
+        .data|map(.name)
+      '
+    )
+    export conf_availability_domain_list_json
+  fi
+  echo "$0: availability_domain_list: $(jq -enr '
+    env.conf_availability_domain_list_json | fromjson |
+    join(", ")
+  ')" >&2
+
+  if test -n "$param_shape"; then
+    conf_shape=$param_shape
+  else
+    echo "$0: error: undefined parameter: $param_shape" >&2
+    exit 2
+  fi
+  echo "$0: shape: $conf_shape" >&2
+
+  if test -n "$param_memory_in_gbs"; then
+    conf_memory_in_gbs=$param_memory_in_gbs
+  else
+    echo "$0: error: undefined parameter: $param_memory_in_gbs" >&2
+    exit 2
+  fi
+  echo "$0: memory_in_gbs: $conf_memory_in_gbs" >&2
+
+  if test -n "$param_ocpus"; then
+    conf_ocpus=$param_ocpus
+  else
+    echo "$0: error: undefined parameter: $param_ocpus" >&2
+    exit 2
+  fi
+  echo "$0: ocpus: $conf_ocpus" >&2
+
+  if test -n "$param_source_id"; then
+    conf_source_id=$param_source_id
+  else
+    conf_source_id=$(
+      export response="$(
+        oci compute image list \
+            --all \
+            --lifecycle-state=AVAILABLE \
+            --operating-system='Canonical Ubuntu' \
+            --compartment-id="$conf_compartment_id" \
+            --shape="$conf_shape" \
+      )"
+
+      jq -enr '
+        env.response | fromjson |
+        .data |
+        sort_by(.["display-name"]) |
+        last |
+        .id
+      '
+    )
+  fi
+  echo "$0: source_id: $conf_source_id" >&2
+
+  if test -n "$param_subnet_id"; then
+    subnet_id=$param_subnet_id
+  else
+    conf_subnet_id=$(
+      export response="$(
+        oci network subnet list \
+            --compartment-id="$conf_compartment_id" \
+            --lifecycle-state=AVAILABLE \
+      )"
+      jq -enr '
+        def assert(cond; msg): if cond then . else error(msg) end;
+
+        env.response | fromjson |
+        .data |
+        assert(length == 1; "could not find exactly one compartment") |
+        .[0] |
+        .id
+      '
+    )
+  fi
+  echo "$0: subnet_id: $conf_subnet_id" >&2
+
+  # This tf_config will create a minimal (not applicable) configuration
+  # which is sufficient to initalize terraform plugins.
+  tf_config > "$conf_workdir"/main.tf.json
+
+  terraform -chdir="$conf_workdir" init
+
+  attempt=0
+  until {
+    attempt=$(expr $attempt + 1)
+    availability_domain=$(
+      jq -enr --argjson attempt "$attempt" '
+        env.conf_availability_domain_list_json | fromjson |
+
+        .[($attempt - 1) % length]
+      '
+    )
+    tf_config \
+        --availability_domain="$availability_domain" \
+        --compartment_id="$conf_compartment_id" \
+        --display_name="$conf_display_name" \
+        --memory_in_gbs="$conf_memory_in_gbs" \
+        --ocpus="$conf_ocpus" \
+        --shape="$conf_shape" \
+        --source_id="$conf_source_id" \
+        --ssh_authorized_key="$conf_ssh_authorized_key" \
+        --subnet_id="$conf_subnet_id" \
+      > "$conf_workdir"/main.tf.json
+    terraform -chdir="$conf_workdir" plan -out "$conf_workdir"/main.tfplan
+    if test "$conf_apply" = true; then
+      terraform -chdir="$conf_workdir" apply "$conf_workdir"/main.tfplan
+    else
+      echo "$0: Not not applying terraform plan" >&2
+    fi
+  }; do
+    echo sleeping... >&2
+    sleep 1m
+  done
+  echo "$0: $(date -Is): success on $attempt. attempt" >&2
+)}
+
+is_ssh_public_key() {
+  {
+    file -b "$1" | grep -Fq 'public key' &&
+    ssh-keygen -l -f "$1"
+  } >/dev/null 2>&1
+}
+
+# usage: tf_config [PARAM...]
+# For possible values of PARAM see for "tf_config parameters" below.
+tf_config() {(
+
+  # tf_config parameters.
+  # Change parameters via arguments using following syntax:
+  #   --NAME=VALUE
+  # where NAME is one of arg_NAME below.
+  #
+  # Example: --display_name=mycomputer
+  arg_availability_domain=
+  arg_compartment_id=
+  arg_display_name=
+  arg_memory_in_gbs=
+  arg_ocpus=
+  arg_shape=
+  arg_source_id=
+  arg_ssh_authorized_key=
+  arg_subnet_id=
+
+  for arg; do
+    case $arg in
+      --*=*)
+        readonly "arg_${arg#--}"
+        ;;
+      *)
+        echo "$0: warning: ignoring unknown argument: $arg" >&2
+    esac
+  done
+
+  nix-instantiate \
+      --eval --json --strict \
+      --argstr availability_domain "$arg_availability_domain" \
+      --argstr compartment_id "$arg_compartment_id" \
+      --argstr display_name "$arg_display_name" \
+      --argstr memory_in_gbs "$arg_memory_in_gbs" \
+      --argstr ocpus "$arg_ocpus" \
+      --argstr source_id "$arg_source_id" \
+      --argstr shape "$arg_shape" \
+      --argstr ssh_authorized_key "$arg_ssh_authorized_key" \
+      --argstr subnet_id "$arg_subnet_id" \
+      -E \
+  '
+    { availability_domain
+    , compartment_id
+    , display_name
+    , memory_in_gbs
+    , ocpus
+    , shape
+    , source_id
+    , ssh_authorized_key
+    , subnet_id
+    }:
+    {
+      terraform.required_providers.oci = {
+        source = "oracle/oci";
+      };
+      provider.oci = {};
+      resource.oci_core_instance.generated_oci_core_instance = {
+        agent_config = {
+          is_management_disabled = "true";
+          is_monitoring_disabled = "true";
+          plugins_config = [
+            {
+              desired_state = "DISABLED";
+              name = "Vulnerability Scanning";
+            }
+            {
+              desired_state = "DISABLED";
+              name = "Compute Instance Monitoring";
+            }
+            {
+              desired_state = "DISABLED";
+              name = "Bastion";
+            }
+          ];
+        };
+        availability_config = {
+          is_live_migration_preferred = "true";
+          recovery_action = "RESTORE_INSTANCE";
+        };
+        availability_domain = availability_domain;
+        compartment_id = compartment_id;
+        create_vnic_details = {
+          assign_private_dns_record = "true";
+          assign_public_ip = "true";
+          subnet_id = subnet_id;
+        };
+        display_name = display_name;
+        instance_options = {
+          are_legacy_imds_endpoints_disabled = "false";
+        };
+        metadata = {
+          ssh_authorized_keys = ssh_authorized_key;
+        };
+        shape = shape;
+        shape_config = {
+          memory_in_gbs = memory_in_gbs;
+          ocpus = ocpus;
+        };
+        source_details = {
+          source_id = source_id;
+          source_type = "image";
+        };
+      };
+    }
+  '
+)}
+
+main "$@"