diff --git a/packages/k8s/src/k8s/index.ts b/packages/k8s/src/k8s/index.ts
index 721bac7..62f5e89 100644
--- a/packages/k8s/src/k8s/index.ts
+++ b/packages/k8s/src/k8s/index.ts
@@ -516,27 +516,37 @@ class BackOffManager {
 export function containerPorts(
   container: ContainerInfo
 ): k8s.V1ContainerPort[] {
-  // 8080:8080/tcp
-  const portFormat = /(\d{1,5})(:(\d{1,5}))?(\/(tcp|udp))?/
-
   const ports: k8s.V1ContainerPort[] = []
   for (const portDefinition of container.portMappings) {
-    const submatches = portFormat.exec(portDefinition)
-    if (!submatches) {
-      throw new Error(
-        `Port definition "${portDefinition}" is in incorrect format`
-      )
+    const portProtoSplit = portDefinition.split('/')
+    if (portProtoSplit.length > 2) {
+      throw new Error(`Unexpected port format: ${portDefinition}`)
     }
+
     const port = new k8s.V1ContainerPort()
-    port.hostPort = Number(submatches[1])
-    if (submatches[3]) {
-      port.containerPort = Number(submatches[3])
+    port.protocol =
+      portProtoSplit.length === 2 ? portProtoSplit[1].toUpperCase() : 'TCP'
+
+    const portSplit = portProtoSplit[0].split(':')
+    if (portSplit.length > 2) {
+      throw new Error('ports should have at most one ":" separator')
     }
-    if (submatches[5]) {
-      port.protocol = submatches[5].toUpperCase()
+
+    const parsePort = (p: string): number => {
+      const num = Number(p)
+      if (!Number.isInteger(num) || num < 1 || num > 65535) {
+        throw new Error(`invalid container port: ${p}`)
+      }
+      return num
+    }
+
+    if (portSplit.length === 1) {
+      port.containerPort = parsePort(portSplit[0])
     } else {
-      port.protocol = 'TCP'
+      port.hostPort = parsePort(portSplit[0])
+      port.containerPort = parsePort(portSplit[1])
     }
+
     ports.push(port)
   }
   return ports
diff --git a/packages/k8s/tests/constants-test.ts b/packages/k8s/tests/constants-test.ts
index 4fc1eb1..cd053fd 100644
--- a/packages/k8s/tests/constants-test.ts
+++ b/packages/k8s/tests/constants-test.ts
@@ -4,6 +4,7 @@ import {
   getSecretName,
   getStepPodName,
   getVolumeClaimName,
+  JOB_CONTAINER_NAME,
   MAX_POD_NAME_LENGTH,
   RunnerInstanceLabel,
   STEP_POD_NAME_SUFFIX_LENGTH
@@ -170,4 +171,12 @@ describe('constants', () => {
       }
     })
   })
+
+  describe('const values', () => {
+    it('should have constants set', () => {
+      expect(JOB_CONTAINER_NAME).toBeTruthy()
+      expect(MAX_POD_NAME_LENGTH).toBeGreaterThan(0)
+      expect(STEP_POD_NAME_SUFFIX_LENGTH).toBeGreaterThan(0)
+    })
+  })
 })
diff --git a/packages/k8s/tests/k8s-utils-test.ts b/packages/k8s/tests/k8s-utils-test.ts
index 3d79256..4341375 100644
--- a/packages/k8s/tests/k8s-utils-test.ts
+++ b/packages/k8s/tests/k8s-utils-test.ts
@@ -1,5 +1,5 @@
 import * as fs from 'fs'
-import { POD_VOLUME_NAME } from '../src/k8s'
+import { containerPorts, POD_VOLUME_NAME } from '../src/k8s'
 import { containerVolumes, writeEntryPointScript } from '../src/k8s/utils'
 import { TestHelper } from './test-setup'
 
@@ -152,5 +152,73 @@ describe('k8s utils', () => {
       volumes = containerVolumes([], false, false)
       expect(volumes.every(e => e.name === POD_VOLUME_NAME)).toBeTruthy()
     })
+
+    it('should parse container ports', () => {
+      const tt = [
+        {
+          spec: '8080:80',
+          want: {
+            containerPort: 80,
+            hostPort: 8080,
+            protocol: 'TCP'
+          }
+        },
+        {
+          spec: '8080:80/udp',
+          want: {
+            containerPort: 80,
+            hostPort: 8080,
+            protocol: 'UDP'
+          }
+        },
+        {
+          spec: '8080/udp',
+          want: {
+            containerPort: 8080,
+            hostPort: undefined,
+            protocol: 'UDP'
+          }
+        },
+        {
+          spec: '8080',
+          want: {
+            containerPort: 8080,
+            hostPort: undefined,
+            protocol: 'TCP'
+          }
+        }
+      ]
+
+      for (const tc of tt) {
+        const got = containerPorts({ portMappings: [tc.spec] })
+        for (const [key, value] of Object.entries(tc.want)) {
+          expect(got[0][key]).toBe(value)
+        }
+      }
+    })
+
+    it('should throw when ports are out of range (0, 65536)', () => {
+      expect(() => containerPorts({ portMappings: ['65536'] })).toThrow()
+      expect(() => containerPorts({ portMappings: ['0'] })).toThrow()
+      expect(() => containerPorts({ portMappings: ['65536/udp'] })).toThrow()
+      expect(() => containerPorts({ portMappings: ['0/udp'] })).toThrow()
+      expect(() => containerPorts({ portMappings: ['1:65536'] })).toThrow()
+      expect(() => containerPorts({ portMappings: ['65536:1'] })).toThrow()
+      expect(() => containerPorts({ portMappings: ['1:65536/tcp'] })).toThrow()
+      expect(() => containerPorts({ portMappings: ['65536:1/tcp'] })).toThrow()
+      expect(() => containerPorts({ portMappings: ['1:'] })).toThrow()
+      expect(() => containerPorts({ portMappings: [':1'] })).toThrow()
+      expect(() => containerPorts({ portMappings: ['1:/tcp'] })).toThrow()
+      expect(() => containerPorts({ portMappings: [':1/tcp'] })).toThrow()
+    })
+
+    it('should throw on multi ":" splits', () => {
+      expect(() => containerPorts({ portMappings: ['1:1:1'] })).toThrow()
+    })
+
+    it('should throw on multi "/" splits', () => {
+      expect(() => containerPorts({ portMappings: ['1:1/tcp/udp'] })).toThrow()
+      expect(() => containerPorts({ portMappings: ['1/tcp/udp'] })).toThrow()
+    })
   })
 })